While the telemetry was still going, you could see Ship engines going out one by one. Earlier when there was video there was what looked like flames visible inside one of the flap hinges, definitely shouldn't be there on ascent. Presumably something failed internally and caused the Ship to shut down before reaching target trajectory, at which point either FTS or the failure itself caused it to blow up, as seen on the Insta reel.

> Something measurable had to go very wrong

Or slightly wrong. An FTS is programmed to be conservative. Particularly on unmanned flights. Doubly particularly on reëntry. Triply so on experiments bits.

It wasn't FTS, it just blew up: https://x.com/SpaceX/status/1880033318936199643