As noted, I get a pop up window (screenshot below) after updating Audition to the latest version (23.6.0.61) on Windows 10 22H2, whenever I use Multitrack > Mixdown Session to New File (either Entire Session or Time Selection causes the problem).
The files used in the multitrack then appear as if they are being worked on, and the waiting symbol appears indefinitely stuck at 100%. The files are unable to be closed or edited in Timeline view, I have to quit the app fully. So far it appears as if the files are rendering correctly before throwing the error.
I have not encountered a data loss issue yet, but this is still a concerning bug.