diff --git a/tests/unit/utils/indexReadiness.test.ts b/tests/unit/utils/indexReadiness.test.ts
index e00d1ff0..75504c71 100644
--- a/tests/unit/utils/indexReadiness.test.ts
+++ b/tests/unit/utils/indexReadiness.test.ts
@@ -29,7 +29,11 @@ function report(overrides: Partial<HealthReport> = {}): HealthReport {
     healthy: true,
     serving: true,
     invariants: [],
-    checkedAt: Date.now(),
+    // A FIXED stamp, never Date.now(): the pin at :98 compares two
+    // independently-built reports, and a live clock made them differ by 1ms
+    // whenever the millisecond ticked between the two calls — a plant-lane
+    // red that had nothing to do with the code under test.
+    checkedAt: 1_700_000_000_000,
     durationMs: 1,
     generation: 1,
     unledgered: [],