Bounce Mix offline makes longer bounce than 'online'

[GregX]

Hi, I've never seen this before: the 'offline bounce' is 3:32 minutes long, with almost a minute of silence at the end, but the online bounce, where you hear the song as it bounces, produces a correct 2:24 minutes long song, with no extra silence at the end. It uses the same selection region for both cases. There is no audio or automation after 2:32.

Nothing I do makes the offline bounce different than 3:32, even selecting four minutes, or two minutes, it always comes out as 3:32.

I've restarted Pro Tools, (ver 21.10.0 Windows), but that had no effect. Is there some setting or something I don't know about? Thanks.