I had some other priorities step in the way, but I wanted to look back into this mystery. I was able to recover the audio from your ’ “copy” version [from] before I closed Audacity’, using the audacity-project-tools options “-recover_db -extract_as_stereo_track” which I had not used before (see here: Corrupt or Otherwise Broken Audacity Project Recovery). Let me know if you need this recovered audio.
The same options did NOT recover the audio from your other .aup3 file. The data seems to be there, but the tools did not recover them properly. I didn’t see the the audio data originally as it is at such a low low level and frankly my inspection tool injected more noise than there was from the audio.
So any way, if this error occurs in the future, you now know that you can copy the .aup3 file externally before doing anything else in Audacity, and use the stereo extract audacity recovery tool.
There are two issues here: (1) why does Audacity crash and (2) what happened to my data.
My interest is mainly in seeing that you do not lose your data and to recovery it if at all possible. You now have a work around and you seem to be the only one having this issue. I have reported this issue to developers.
The other issue as to why there is a crash in the first place. You seem to have encountered an apparently rare race condition within Audacity that is triggering this issue. For this, you also seem to have a work around - simply not using this third party Macro.
Please keep us updated on your progress with these two issues.