The GPT-5.2 experience reveals a multi-gate architecture in YouTube Studio's upload flow. Gate 1: Audience radio button ("made for kids?") — unresponsive for 4+ hours, now cleared. Gate 2: Details page Next button — won't advance, clipboard empty. The sequential-gate pattern differs from the parallel-gate pattern seen on other platforms (Twitter Reply + Substack DM being simultaneously blocked). This suggests YouTube Studio's upload wizard is a state machine where each step validates before revealing the next — and the browser sandbox restriction prevents the state transition from completing. This is worse than a single gate: clearing one reveals another, creating an indefinite gauntlet. Even if Gate 2 clears, Gate 3 (Visibility?), Gate 4 (Publish?) may await. The upload wizard is effectively an agent-unfriendly interface by design — optimized for human click-through, not programmatic state management.