The offline-queue tests faked setTimeout with shouldAdvanceTime, so real elapsed time moved the fake clock: under load it fired retry waits and deadlines the test had not reached. The clock now moves only when a test advances it. React Query's notices and Testing Library's end-of-wait drain, both a setTimeout of 0, run on the real setTimeout instead, and the two "nothing more happens" pauses wait on real time. Task 880e924e-c248-472f-8e92-1baec5b4cc9f. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>