diff --git a/deploy/sync-mirror.sh b/deploy/sync-mirror.sh
index 4446c49..a1b6b96 100755
--- a/deploy/sync-mirror.sh
+++ b/deploy/sync-mirror.sh
@@ -230,7 +230,9 @@ sync_github_to_forgejo_with_prs() {
             BRANCH_SHA=$(git rev-parse "refs/remotes/origin/$branch" 2>/dev/null || true)
         fi
         if [ -n "$BRANCH_SHA" ]; then
-            TRACKED_PR=$(sqlite3 "$PIPELINE_DB" "SELECT pr_number FROM sync_autocreate_tracker WHERE branch=$(printf "'%s'" "${branch//\'/\'\'}") AND sha=$(printf "'%s'" "$BRANCH_SHA") LIMIT 1;" 2>/dev/null || true)
+            # stderr → $LOG so sustained sqlite3 contention surfaces in ops logs
+            # rather than silently falling through to a redundant auto-create.
+            TRACKED_PR=$(sqlite3 "$PIPELINE_DB" "SELECT pr_number FROM sync_autocreate_tracker WHERE branch=$(printf "'%s'" "${branch//\'/\'\'}") AND sha=$(printf "'%s'" "$BRANCH_SHA") LIMIT 1;" 2>>"$LOG" || echo "")
             if [ -n "$TRACKED_PR" ]; then
                 log "Skip auto-create: $branch SHA $BRANCH_SHA already tracked (PR #$TRACKED_PR)"
                 continue
@@ -310,8 +312,13 @@ print('no')
         # Record (branch, sha, pr_number) so the tracker gate above can short-
         # circuit the next time we see this exact (branch, sha) combination.
         # INSERT OR IGNORE: idempotent if a concurrent run already inserted.
+        # WARN log on failure: silent INSERT failure under sustained sqlite3
+        # contention would mask the loop reappearing on the next cycle (HAS_PR
+        # only saves us while the closed PR is in the 50-item pagination window).
         if [ -n "$BRANCH_SHA" ] && [[ "$PR_NUM" =~ ^[0-9]+$ ]]; then
-            sqlite3 "$PIPELINE_DB" "INSERT OR IGNORE INTO sync_autocreate_tracker (branch, sha, pr_number) VALUES ($(printf "'%s'" "${branch//\'/\'\'}"), $(printf "'%s'" "$BRANCH_SHA"), $PR_NUM);" 2>/dev/null || true
+            if ! sqlite3 "$PIPELINE_DB" "INSERT OR IGNORE INTO sync_autocreate_tracker (branch, sha, pr_number) VALUES ($(printf "'%s'" "${branch//\'/\'\'}"), $(printf "'%s'" "$BRANCH_SHA"), $PR_NUM);" 2>>"$LOG"; then
+                log "WARN: tracker insert failed for $branch SHA $BRANCH_SHA (PR #$PR_NUM) — duplicate auto-create possible next cycle"
+            fi
         fi
 
         # Step 4.5: Link GitHub PR to Forgejo PR in pipeline DB