I dunno, it looks like a nominal shutdown to me. The speed readout shows rapidly decreasing acceleration just as the engine displays go out instead of the telemetry suddenly going stale as you'd expect if it just blew up during the burn. Then, after the acceleration has gone to zero, the telemetry goes stale, so my guess would be on something going wrong during shutdown (ullage collapse when the propellant sloshes forward as the engines shut down maybe, this was a problem during the first landing test.)

AFTS seems unlikely this late in the burn, I think they said it was in terminal guidance and it's very hard to laterally change the impact point in any meaningful way with that much velocity. But I agree, it definitely looked like something's venting near the end, too.