While the support given on this forum is SENSATIONAL...before bailing on BIAB have you contacted PG Tech Support?

I would imagine they would ask you to send them the file you created to see if they can reproduce/troubleshoot your issue.

Also...just a wild guess/stab in the dark. But if I read you correctly you are attempting to do 2 different things with the ending.

1. Slow the tempo down...sort of a rubato ending correct?

2. Fade out the volume.

It occurs to me that attempting to do both in the same bars may be causing some sort of conflict during the render from BIAB to wav.

Just a guess.

Best,
Jim