diff --git a/backend/app/tasks/ml.py b/backend/app/tasks/ml.py
index 708aa22..ecdfcbd 100644
--- a/backend/app/tasks/ml.py
+++ b/backend/app/tasks/ml.py
@@ -760,10 +760,11 @@ def enqueue_gpu_backfill(task_name: str) -> int:
         sel = sa_select(
             ImageRecord.id, literal(task_name), literal("pending")
         ).where(~already)
-        result = session.execute(
-            insert(GpuJob).from_select(
-                ["image_record_id", "task", "status"], sel
-            )
-        )
+        # RETURNING + count: result.rowcount is unreliable for INSERT…SELECT.
+        rows = session.execute(
+            insert(GpuJob)
+            .from_select(["image_record_id", "task", "status"], sel)
+            .returning(GpuJob.id)
+        ).fetchall()
         session.commit()
-        return result.rowcount or 0
+        return len(rows)