Hello Johnny,
Sorry to hear you are experiencing bounce bugs with 3.6.7 and Logic Pro 9.1.6.
I attempted to reproduce your bug by bouncing an existing Pianoteq track in Logic Pro 9.1.6, ... and had no problem doing so.
Just for fun, I looked at what version of Pianoteq I was using. Lo and behold!! I was only running Pianoteq Pro Version 3.6.5!!! Upon leaping to Pianoteq's download screen, I immediately downloaded and installed the 3.6.7 version of Pianoteq Pro and tried again.
The same non-problem issue arose when I attempted to bounce. It worked perfectly.
Here are a few items for thought as I ponder your problem:
I happen to be running the 32-bit version of Logic Pro 9.1.6; by chance are you running the 64-bit version??? If so, you might wish to try switching back to 32 bit to see if anything happens.
It turns out that version 9.1.6 is a somewhat new update of Apple Logic Pro 9. Question for you: Were you able to bounce Pianoteq 3.6.7 in Logic Pro's previous version??? I don't know the answer to this question; rather, I am suggesting some troubleshooting routes.
My version of Pianoteq 3.6.7 is Pianoteq PRO. I don't know what version you are running (Pro, Standard, Play), and I don't know if there is a bug in either the Standard or Play version -- but I assure you that Pianoteq PRO version 3.6.7 does bounce with complete stability.
Perhaps this may open the field for questions or responses from Modartt.
Hope this helps,
Cheers,
Joe