diff --git a/js/nostr/client.js b/js/nostr/client.js
index c66becd8..83335dfc 100644
--- a/js/nostr/client.js
+++ b/js/nostr/client.js
@@ -3482,7 +3482,14 @@ export class NostrClient {
    * @param {function} [params.fetchFn] - Custom fetch function (mocks or specialized logic). Defaults to `pool.list`.
    * @returns {Promise<import("nostr-tools").Event[]>} Deduplicated list of events found across all relays.
    */
-  async fetchListIncrementally({ kind, pubkey, dTag, relayUrls, fetchFn } = {}) {
+  async fetchListIncrementally({
+    kind,
+    pubkey,
+    dTag,
+    relayUrls,
+    fetchFn,
+    since,
+  } = {}) {
     if (!kind || !pubkey) {
       throw new Error("fetchListIncrementally requires kind and pubkey");
     }
@@ -3514,7 +3521,23 @@ export class NostrClient {
 
     for (const chunk of chunks) {
       const promises = chunk.map(async (relayUrl) => {
-        const lastSeen = this.getSyncLastSeen(kind, normalizedPubkey, dTag, relayUrl);
+        let lastSeen = this.getSyncLastSeen(
+          kind,
+          normalizedPubkey,
+          dTag,
+          relayUrl,
+        );
+
+        // If an explicit 'since' override is provided, use it instead of storage.
+        // This allows services to anchor fetching to their own known state.
+        if (since !== undefined) {
+          const overrideSince = Number(since);
+          lastSeen =
+            Number.isFinite(overrideSince) && overrideSince >= 0
+              ? Math.floor(overrideSince)
+              : 0;
+        }
+
         const filter = {
           kinds: [kind],
           authors: [normalizedPubkey],
diff --git a/js/services/hashtagPreferencesService.js b/js/services/hashtagPreferencesService.js
index 4eba4f25..f1535d77 100644
--- a/js/services/hashtagPreferencesService.js
+++ b/js/services/hashtagPreferencesService.js
@@ -477,12 +477,20 @@ class HashtagPreferencesService {
       // fetchListIncrementally takes a single kind.
       // kinds is array of [canonicalKind, legacyKind] if different.
 
-      const promises = kinds.map(kind => nostrClient.fetchListIncrementally({
-        kind,
-        pubkey: normalized,
-        dTag: HASHTAG_IDENTIFIER,
-        relayUrls: relays
-      }));
+      // Anchor the fetch to the service's current state to prevent desync.
+      // If we have cached data, we ask for updates since that timestamp.
+      // If we have no data, we force a full fetch (since=0).
+      const since = wasLoadedForUser ? Number(this.eventCreatedAt) || 0 : 0;
+
+      const promises = kinds.map((kind) =>
+        nostrClient.fetchListIncrementally({
+          kind,
+          pubkey: normalized,
+          dTag: HASHTAG_IDENTIFIER,
+          relayUrls: relays,
+          since,
+        }),
+      );
 
       const results = await Promise.all(promises);
       events = results.flat();
diff --git a/tests/nostr/client.test.mjs b/tests/nostr/client.test.mjs
index f64f8e8f..97e84cbd 100644
--- a/tests/nostr/client.test.mjs
+++ b/tests/nostr/client.test.mjs
@@ -85,6 +85,40 @@ describe("NostrClient", () => {
       // pool.list is called with ([url], [filter]), so arguments[1] is an array
       assert.equal(filter[0].since, 101);
     });
+
+    it("should override lastSeen with explicit since parameter", async () => {
+      // Mock syncMetadataStore to return something high
+      client.syncMetadataStore.getLastSeen = () => 500;
+
+      await client.fetchListIncrementally({
+        kind: 1,
+        pubkey: "abc",
+        relayUrls: ["wss://relay.example.com"],
+        since: 100 // Explicit override, should be used instead of 500
+      });
+
+      // Verify filter used 'since + 1'
+      const call = mockPool.list.mock.calls[0];
+      const filter = call.arguments[1];
+      assert.equal(filter[0].since, 101);
+    });
+
+    it("should force full fetch if since is 0", async () => {
+      // Mock syncMetadataStore to return something
+      client.syncMetadataStore.getLastSeen = () => 500;
+
+      await client.fetchListIncrementally({
+        kind: 1,
+        pubkey: "abc",
+        relayUrls: ["wss://relay.example.com"],
+        since: 0 // Force full fetch
+      });
+
+      const call = mockPool.list.mock.calls[0];
+      const filter = call.arguments[1];
+      // Should NOT have 'since' property
+      assert.equal(filter[0].since, undefined);
+    });
   });
 
   describe("subscribeVideos", () => {