I think that's the ascent burn. It doesn't look like the engines re-lit at all for the descent. (I imagine they aren't supposed to light until they're a lot closer to the ground than they were when the video was lost.)
At altitude 22km superheavy was moving at 4310 kmh (34:18 in linked video) speed then dropped continually, at 34:45 in the video the icons show that 3 engines were lit, altitude was 1km and speed was 1300 kmh. At 34:49 you can see flames, speed continues to drop, then you see the sea rushing up, then it cuts