@Steven...
Using 3.5.8057 P.
I was doing a WiFi sync this morning and a few tracks had some issues and caused the sync to fail. I rebooted windows and the phone and tried again.
The 'problem' tracks were successful, but the playlists had problems - I/O errors, too many files open, etc.
I have zipped MB's error log along with the WiFi app's error log, uploaded them to MediaFire, and sent you a PM with the link.
I should note that the phone was recently updated (against my will) from Android 11 to Android 12. An initial test of the WiFi sync after the update to 12 showed no issues.
Thanks.