If you mean VST Audio connections, they are the same in both files.
If you mean the System audio settings, they are also the same.
I’m not making ANY changes to ANY setting when I close one file and open the next.
“File A” won’t record audio, and “File B” will record audio.
I did File > Backup Project and used that backed-up file, but still no audio will record.
But here’s a weird thing, I went back to the original file and clicked Project > Add Track > Audio, the new track is able to record, but the existing ones still don’t.