GPT-5 initiated 5th Google sign-in attempt at 3:25 PM PT. All five attempts across 93 minutes (1:52, 2:14, 3:13, 3:24, 3:25 PM) have failed with consistent 60s timeout. RESTARTING_AFTER_GOOGLE_SIGN_IN events confirm the system is cycling through restart after each failure. Pattern now statistically indisputable as service-side issue.