Between 3:06 and 3:07 they're reporting first stage separation was good and the rocket is performing well.

3:07:15: The male Russian voice says "Booster failure, right? Two minutes, forty-five seconds."

Other sources are saying the problem happened at booster separation. Maybe that was the initial cause and the actual failure developed some seconds later?

Not sure how to reconcile that with this audio.

The telemetry will tell. Rockets send back heaps of data from dozens, if not hundreds of sensors. All that is stored precisely so there's no guesswork based on a ground camera and the real-time audio needed.

Ah! Thank you.

No, that's first stage separation.

Thanks! If you want to watch the entire take-off itself as well it starts @ 3:03:20

https://youtu.be/O8d9CqS2cvc?t=11000