diff --git a/backend/internal/runner/runner.go b/backend/internal/runner/runner.go
index 24f4757..f9c85a4 100644
--- a/backend/internal/runner/runner.go
+++ b/backend/internal/runner/runner.go
@@ -248,23 +248,30 @@ func (r *Runner) poll(ctx context.Context, scrapeSem, audioSem chan struct{}, wg
 	}
 
 	// ── Audio tasks ───────────────────────────────────────────────────────
+	// Only claim tasks when there is a free slot in the semaphore.
+	// This avoids the old bug where we claimed (status→running) a task and
+	// then couldn't dispatch it, leaving it orphaned until the reaper fired.
+audioLoop:
 	for {
 		if ctx.Err() != nil {
 			return
 		}
+		// Check capacity before claiming to avoid orphaning tasks.
+		select {
+		case audioSem <- struct{}{}:
+			// Slot acquired — proceed to claim a task.
+		default:
+			// All slots busy; leave remaining pending tasks for next tick.
+			break audioLoop
+		}
 		task, ok, err := r.deps.Consumer.ClaimNextAudioTask(ctx, r.cfg.WorkerID)
 		if err != nil {
+			<-audioSem // release the pre-acquired slot
 			r.deps.Log.Error("runner: ClaimNextAudioTask failed", "err", err)
 			break
 		}
 		if !ok {
-			break
-		}
-		select {
-		case audioSem <- struct{}{}:
-		default:
-			r.deps.Log.Warn("runner: audio semaphore full, will retry next tick",
-				"task_id", task.ID)
+			<-audioSem // release the pre-acquired slot; queue empty
 			break
 		}
 		r.tasksRunning.Add(1)
diff --git a/backend/internal/storage/pocketbase.go b/backend/internal/storage/pocketbase.go
index 23e1fdc..53d724a 100644
--- a/backend/internal/storage/pocketbase.go
+++ b/backend/internal/storage/pocketbase.go
@@ -247,8 +247,9 @@ func (c *pbClient) claimRecord(ctx context.Context, collection, workerID string,
 	}
 
 	claim := map[string]any{
-		"status":    string(domain.TaskStatusRunning),
-		"worker_id": workerID,
+		"status":       string(domain.TaskStatusRunning),
+		"worker_id":    workerID,
+		"heartbeat_at": time.Now().UTC().Format(time.RFC3339),
 	}
 	for k, v := range extraClaim {
 		claim[k] = v