diff --git a/workspace-server/internal/pendinguploads/sweeper_test.go b/workspace-server/internal/pendinguploads/sweeper_test.go
index b1a723a6..e1bce986 100644
--- a/workspace-server/internal/pendinguploads/sweeper_test.go
+++ b/workspace-server/internal/pendinguploads/sweeper_test.go
@@ -280,9 +280,13 @@ func TestStartSweeper_RecordsMetricsOnSuccess(t *testing.T) {
 	// vs-metric-record race (see waitForMetricDelta comment).
 	waitForMetricDelta(t, deltaAcked, 3, 2*time.Second)
 	waitForMetricDelta(t, deltaExpired, 5, 2*time.Second)
-	// Error counter MUST stay at zero on the success path. Read after
-	// the success counters have settled — once those are correct,
-	// StartSweeper has fully processed this cycle's result.
+	// Error counter MUST stay at zero on the success path. Poll for it to
+	// settle first — a goroutine from a prior test (e.g.
+	// TestStartSweeper_TransientErrorDoesNotCrashLoop) may still be running
+	// and incrementing errorCount after its metricDelta() baseline was
+	// captured. This race manifests as deltaError=1 on success-path
+	// assertions in slow -race CI runs (#22 fix).
+	waitForMetricDelta(t, deltaError, 0, 2*time.Second)
 	if got := deltaError(); got != 0 {
 		t.Errorf("error counter delta = %d, want 0", got)
 	}