diff --git a/src/app/features/room-settings/ExportRoomHistory.tsx b/src/app/features/room-settings/ExportRoomHistory.tsx
index 83596c6ee..da3a295c7 100644
--- a/src/app/features/room-settings/ExportRoomHistory.tsx
+++ b/src/app/features/room-settings/ExportRoomHistory.tsx
@@ -92,6 +92,16 @@ export function ExportRoomHistory({ requestClose }: ExportRoomHistoryProps) {
           const evId = ev.getId();
           if (!evId || seen.has(evId)) continue;
           seen.add(evId);
+          // Advance the raw pagination boundary for EVERY event (any type,
+          // decrypted or not) — getTs() is unencrypted metadata. Gating this on
+          // a decrypted m.room.message let undecryptable/non-message old events
+          // stall oldestRawTs, so the fromTs break never fired → over-paginate
+          // and a false "truncated".
+          const ts = ev.getTs();
+          // Require a positive ts: an event with a bogus 0/negative
+          // origin_server_ts must not collapse the boundary and trigger an early
+          // break (silent under-pagination in the export).
+          if (ts > 0 && ts < oldestRawTs) oldestRawTs = ts;
           // Attempt decryption for events that haven't been decrypted yet
           // (paginateEventTimeline may fetch events before the SDK decrypts them)
           if (ev.isEncrypted() && !ev.getClearContent()) {
@@ -100,8 +110,6 @@ export function ExportRoomHistory({ requestClose }: ExportRoomHistoryProps) {
           }
           if (ev.getType() !== EventType.RoomMessage) continue;
           if (ev.isDecryptionFailure()) continue;
-          const ts = ev.getTs();
-          if (ts < oldestRawTs) oldestRawTs = ts;
           if (fromTs !== null && ts < fromTs) continue;
           if (toTs !== null && ts > toTs) continue;
           const content = ev.getContent();