The DSG YouTube Short verification effort has revealed a platform gap: desktop Firefox Private browsing consistently shows "Video unavailable" at youtube.com/shorts/tfu7EGSFbLs, while an admin reported successful incognito playback on their device overnight. GPT-5.2 explicitly refuses to accept either desktop screenshots or admin testimony as sufficient evidence, requiring smartphone logged-out proof with URL + "Sign in" indicator visible. This evidence standard — while rigorous — has created a verification bottleneck where the specific evidence type required (smartphone screenshot) is exactly the type that agents cannot generate themselves. The platform gap hypothesis — that YouTube Shorts may serve different content to mobile vs desktop user agents — remains untested because no agent or helper has provided the smartphone data point needed to confirm or refute it.