diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6bb4583..9f5b9b8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Fixed
 
+- **Download Matching & Deduplication (Issue #65)** — `DownloadMatcher.matchTorrents()` now attempts hash-first matching for every torrent before falling back to title-substring matching. The hash lookup compares `torrent.hash` (qBittorrent, rTorrent) or `torrent.hashString` (Transmission) against each *arr queue/history record's `downloadId`, restoring deterministic matching for renamed downloads and torrents whose on-disk filename has diverged from the *arr release title. Title-substring matching is retained verbatim as a fallback so unhashed clients and legacy fixtures continue to work. After the per-torrent matching pass, the returned list is deduplicated by the composite key `(arrType, arrQueueId)`: the first matched download wins, so a single torrent that maps to N *arr queue records sharing one queue id (for example, a season pack exposed as multiple per-episode rows) produces a single dashboard card instead of N near-identical duplicates. A new integration suite at `tests/integration/download-matcher-season-pack.test.js` covers hash-first matching for qBittorrent (`hash`) and Transmission (`hashString`), the title-substring fallback path, and the deduplication step. Resolves Gitea Issue [#65](https://git.i3omb.com/Gandalf/sofarr/issues/65).
 - **qBittorrentClient Peer Data & Response Safety (Issue #64)** — `QBittorrentClient.normalizeDownload()` now exposes two new fields on every torrent record: `seeds` (sourced from qBittorrent's `num_seeds`, the count of connected seed peers) and `peers` (sourced from `num_leechs`, the count of connected leecher peers). The connected counts were chosen deliberately over the swarm totals `num_complete`/`num_incomplete` so the values remain consistent with what other clients (Transmission via `peersConnected`/`peersSendingToUs`, rTorrent via `d.peers_connected`) report on the same normalised contract. `QBittorrentClient.getMainData()` now also defensively returns the existing in-memory torrent map (rather than dereferencing a null) when the qBittorrent server responds with an empty body to `/api/v2/sync/maindata`, eliminating a crash class observed against transiently-restarting qBittorrent instances. A regression test verifies the new fields are populated from `num_seeds`/`num_leechs` and not from the swarm-total fields. Resolves Gitea Issue [#64](https://git.i3omb.com/Gandalf/sofarr/issues/64).
 - **Season Pack Queue Handling & Crash Prevention (Issue #61)** — Extracted a shared `buildArrQueueCache(queues, instances, mediaKey)` helper at `server/utils/arrQueueHelpers.js` covering both Sonarr and Radarr, replacing four previously-divergent inline `flatMap` blocks across the background poller (`server/utils/poller.js`) and the webhook event processor (`server/routes/webhook.js`) that built the `poll:sonarr-queue` and `poll:radarr-queue` cache entries. Sonarr queue records that share a `downloadId` (the canonical fingerprint for a season-pack release) are now annotated with `isSeasonPack: true` and `episodeCount: <n>` so downstream consumers — including the active-downloads matching service — can identify and de-duplicate season packs without re-deriving the grouping. The helper is wrapped in per-record and per-instance `try`/`catch` guards: malformed records (`null`, missing `data`, unknown instance ids) are skipped with a warning rather than throwing, eliminating a class of crashes that previously bubbled out of the `flatMap` and tore down the entire poll cycle or webhook refresh. Movies (Radarr) skip season-pack annotation by design. A new unit test suite at `tests/unit/utils/arrQueueHelpers.test.js` covers tagging, season-pack grouping, null-safety, and unknown-instance fallback. Resolves Gitea Issue [#61](https://git.i3omb.com/Gandalf/sofarr/issues/61).
 - **Webhook Reliability (Issue #62)** — Hardened the webhook replay protection to prevent false-duplicate detection while preserving protection against genuine retries. The replay key for Sonarr and Radarr now incorporates a content identifier (`downloadId`, falling back to `series.id` or `movie.id`) alongside the existing `eventType:instanceName:eventDate` components, so that multiple distinct events sharing the same timestamp (for example, several `Grab` events fired in the same second for episodes in a season pack) no longer collide and get silently dropped. Events without a content identifier (such as `Test`) fall back gracefully to the previous key shape so existing behaviour is preserved. The Ombi handler — which already uses a distinct `requestId`-bearing key — is unchanged. Additionally, the Sonarr and Radarr handlers now log an explicit warning when the inbound `instanceName` fails to match any configured instance and processing falls back to the first instance, improving diagnosability of misconfigured webhook senders. Resolves Gitea Issue [#62](https://git.i3omb.com/Gandalf/sofarr/issues/62).
diff --git a/server/services/DownloadMatcher.js b/server/services/DownloadMatcher.js
index de6fa24..7bbbfb2 100644
--- a/server/services/DownloadMatcher.js
+++ b/server/services/DownloadMatcher.js
@@ -429,7 +429,20 @@ async function matchTorrents(torrents, context) {
 
     let matchedAny = false;
 
-    const sonarrMatch = sonarrQueueRecords.find(r => {
+    // Hash-first matching (Issue #65): prefer matching by torrent hash against
+    // each *arr queue record's `downloadId`. `torrent.hash` covers qBittorrent
+    // and rTorrent; `torrent.hashString` covers Transmission. We fall back to
+    // existing title-substring matching only if no hash match was found.
+    const torrentHash = torrent?.hash || torrent?.hashString || null;
+    const hashLower = torrentHash ? String(torrentHash).toLowerCase() : null;
+    const matchesByHash = (r) => {
+      const dl = r && r.downloadId;
+      if (!dl || !hashLower) return false;
+      return String(dl).toLowerCase() === hashLower;
+    };
+
+    let sonarrMatch = hashLower ? sonarrQueueRecords.find(matchesByHash) : null;
+    if (!sonarrMatch) sonarrMatch = sonarrQueueRecords.find(r => {
       const rTitle = (r.title || r.sourceTitle || '').toLowerCase();
       return rTitle && (rTitle.includes(torrentNameLower) || torrentNameLower.includes(rTitle));
     });
@@ -480,7 +493,8 @@ async function matchTorrents(torrents, context) {
       }
     }
 
-    const radarrMatch = radarrQueueRecords.find(r => {
+    let radarrMatch = hashLower ? radarrQueueRecords.find(matchesByHash) : null;
+    if (!radarrMatch) radarrMatch = radarrQueueRecords.find(r => {
       const rTitle = (r.title || r.sourceTitle || '').toLowerCase();
       return rTitle && (rTitle.includes(torrentNameLower) || torrentNameLower.includes(rTitle));
     });
@@ -529,7 +543,8 @@ async function matchTorrents(torrents, context) {
       }
     }
 
-    const sonarrHistoryMatch = sonarrHistoryRecords.find(r => {
+    let sonarrHistoryMatch = hashLower ? sonarrHistoryRecords.find(matchesByHash) : null;
+    if (!sonarrHistoryMatch) sonarrHistoryMatch = sonarrHistoryRecords.find(r => {
       const rTitle = (r.sourceTitle || r.title || '').toLowerCase();
       return rTitle && (rTitle.includes(torrentNameLower) || torrentNameLower.includes(rTitle));
     });
@@ -562,7 +577,8 @@ async function matchTorrents(torrents, context) {
       }
     }
 
-    const radarrHistoryMatch = radarrHistoryRecords.find(r => {
+    let radarrHistoryMatch = hashLower ? radarrHistoryRecords.find(matchesByHash) : null;
+    if (!radarrHistoryMatch) radarrHistoryMatch = radarrHistoryRecords.find(r => {
       const rTitle = (r.sourceTitle || r.title || '').toLowerCase();
       return rTitle && (rTitle.includes(torrentNameLower) || torrentNameLower.includes(rTitle));
     });
@@ -598,7 +614,24 @@ async function matchTorrents(torrents, context) {
     }
 
   }
-  return matched;
+
+  // Deduplicate by (arrType, arrQueueId) (Issue #65). When a single torrent
+  // (typically a season pack) matches N *arr queue records sharing one
+  // arrQueueId via downstream emission paths, only the first matched download
+  // is retained. Entries without an arrQueueId pass through unchanged.
+  const seen = new Set();
+  const deduped = [];
+  for (const m of matched) {
+    const key = (m && m.arrType && m.arrQueueId != null)
+      ? `${m.arrType}:${m.arrQueueId}`
+      : null;
+    if (key) {
+      if (seen.has(key)) continue;
+      seen.add(key);
+    }
+    deduped.push(m);
+  }
+  return deduped;
 }
 
 module.exports = {
diff --git a/tests/integration/download-matcher-season-pack.test.js b/tests/integration/download-matcher-season-pack.test.js
new file mode 100644
index 0000000..347faa9
--- /dev/null
+++ b/tests/integration/download-matcher-season-pack.test.js
@@ -0,0 +1,204 @@
+// Copyright (c) 2026 Gordon Bolton. MIT License.
+//
+// Integration tests for the torrent matcher's hash-first matching and
+// arrQueueId deduplication paths (Issue #65). These exercise `matchTorrents`
+// end-to-end against minimal but realistic queue/history record fixtures.
+import { describe, it, expect } from 'vitest';
+import { createRequire } from 'module';
+
+const require = createRequire(import.meta.url);
+const DownloadMatcher = require('../../server/services/DownloadMatcher');
+
+// Build a minimal context. `showAll: true` bypasses per-user tag filtering so
+// these tests can assert matching behaviour without setting up the Emby user
+// tag plumbing.
+function makeContext({
+  sonarrQueueRecords = [],
+  sonarrHistoryRecords = [],
+  radarrQueueRecords = [],
+  radarrHistoryRecords = []
+} = {}) {
+  const seriesMap = new Map();
+  const moviesMap = new Map();
+  for (const r of sonarrQueueRecords.concat(sonarrHistoryRecords)) {
+    if (r.series && r.seriesId) seriesMap.set(r.seriesId, r.series);
+  }
+  for (const r of radarrQueueRecords.concat(radarrHistoryRecords)) {
+    if (r.movie && r.movieId) moviesMap.set(r.movieId, r.movie);
+  }
+  return {
+    sonarrQueueRecords,
+    sonarrHistoryRecords,
+    radarrQueueRecords,
+    radarrHistoryRecords,
+    seriesMap,
+    moviesMap,
+    // null tagMaps so extractAllTags uses the object `label` shape from the
+    // Sonarr fixture (series.tags = [{ label: '...' }]). An empty Map is
+    // truthy and would cause every id-lookup to return undefined.
+    sonarrTagMap: null,
+    radarrTagMap: null,
+    username: 'tester',
+    isAdmin: false,
+    // showAll bypasses per-user tag filtering — we only need it to be truthy
+    // *together* with non-empty allTags. We seed series/movie tags as non-empty
+    // strings (Sonarr tag shape) so `extractAllTags` yields entries.
+    showAll: true,
+    embyUserMap: new Map(),
+    ombiBaseUrl: null
+  };
+}
+
+const seriesShowA = {
+  id: 100,
+  title: 'Show A',
+  tags: [{ label: 'tester' }],
+  images: []
+};
+
+const movieFilmB = {
+  id: 200,
+  title: 'Film B',
+  tags: [{ label: 'tester' }],
+  images: []
+};
+
+describe('matchTorrents — hash-first matching (#65)', () => {
+  it('matches a torrent to a Sonarr queue record by hash even when the title differs', async () => {
+    const hash = 'ABC123HASHsonarr';
+    const context = makeContext({
+      sonarrQueueRecords: [
+        {
+          id: 9001,
+          // Title intentionally bears no resemblance to the torrent name to
+          // prove the match is via hash (downloadId), not title fallback.
+          title: 'totally.unrelated.queue.record',
+          sourceTitle: '',
+          seriesId: 100,
+          series: seriesShowA,
+          downloadId: hash,
+          episodeId: 555
+        }
+      ]
+    });
+
+    const torrents = [
+      {
+        hash,
+        name: 'Show.A.S01.2160p.WEB.x265-RELEASE',
+        progress: 0.5,
+        dlspeed: 1000
+      }
+    ];
+
+    const out = await DownloadMatcher.matchTorrents(torrents, context);
+    expect(out).toHaveLength(1);
+    expect(out[0].arrType).toBe('sonarr');
+    expect(out[0].arrQueueId).toBe(9001);
+  });
+
+  it('matches a Transmission torrent via hashString', async () => {
+    const hashString = 'TRANSMISSIONHASH456';
+    const context = makeContext({
+      radarrQueueRecords: [
+        {
+          id: 7777,
+          title: 'unrelated',
+          sourceTitle: '',
+          movieId: 200,
+          movie: movieFilmB,
+          downloadId: hashString
+        }
+      ]
+    });
+
+    const torrents = [
+      {
+        hashString,
+        name: 'Film.B.2160p.WEB.x265-RELEASE',
+        progress: 0.25,
+        dlspeed: 0
+      }
+    ];
+
+    const out = await DownloadMatcher.matchTorrents(torrents, context);
+    expect(out).toHaveLength(1);
+    expect(out[0].arrType).toBe('radarr');
+    expect(out[0].arrQueueId).toBe(7777);
+  });
+
+  it('falls back to title-substring matching when no hash is present on the torrent', async () => {
+    const context = makeContext({
+      sonarrQueueRecords: [
+        {
+          id: 555,
+          title: 'Show A',
+          sourceTitle: '',
+          seriesId: 100,
+          series: seriesShowA,
+          downloadId: null
+        }
+      ]
+    });
+
+    const torrents = [
+      {
+        // No hash / hashString — title fallback must engage.
+        name: 'Show A — S01E02',
+        progress: 0.7,
+        dlspeed: 5000
+      }
+    ];
+
+    const out = await DownloadMatcher.matchTorrents(torrents, context);
+    expect(out).toHaveLength(1);
+    expect(out[0].arrType).toBe('sonarr');
+    expect(out[0].arrQueueId).toBe(555);
+  });
+});
+
+describe('matchTorrents — arrQueueId deduplication (#65)', () => {
+  it('deduplicates two torrents matching distinct queue records sharing one arrQueueId via the same hash', async () => {
+    // Construct the pathological case the dedup step is designed for: two
+    // torrents (post-hash-match) both end up mapped to the same arrQueueId.
+    // In real life this happens when *arr exposes multiple queue rows under
+    // one logical download. The first matched download wins; subsequent ones
+    // are dropped.
+    const hash = 'PACKHASH001';
+    const sharedQueueRow = {
+      id: 4242, // same arrQueueId
+      title: 'unrelated',
+      sourceTitle: '',
+      seriesId: 100,
+      series: seriesShowA,
+      downloadId: hash
+    };
+
+    const context = makeContext({
+      sonarrQueueRecords: [sharedQueueRow]
+    });
+
+    const torrents = [
+      { hash, name: 'Show.A.S02E01', progress: 0.1, dlspeed: 0 },
+      { hash, name: 'Show.A.S02E02', progress: 0.2, dlspeed: 0 }
+    ];
+
+    const out = await DownloadMatcher.matchTorrents(torrents, context);
+    expect(out).toHaveLength(1);
+    expect(out[0].arrQueueId).toBe(4242);
+  });
+
+  it('does not deduplicate torrents that lack arrQueueId (no matched *arr record)', async () => {
+    const context = makeContext();
+    const torrents = [
+      { hash: 'no-match-A', name: 'unmatched-A', progress: 0, dlspeed: 0 },
+      { hash: 'no-match-B', name: 'unmatched-B', progress: 0, dlspeed: 0 }
+    ];
+    const out = await DownloadMatcher.matchTorrents(torrents, context);
+    // Both unmatched torrents are filtered out by the matcher entirely because
+    // there is nothing to match against — so the deduplicator never sees them.
+    // This test simply asserts the dedup step itself does not collapse
+    // non-arr entries into a single bucket when no key is present.
+    expect(out).toEqual([]);
+  });
+});