M4A suddenly stopped working on Synology

Been fine for years. Now it just skips over any M4A tracks. The log looks like this: https://paste.ubuntu.com/p/FPKv9VfqsJ/

Logitech Media Server Version: 7.9.2

I made sure I have the right executables and entries in my convert.conf, per the wiki. And I checked that the files are fine, and their permissions are the same as everything else in the library.

I really want to hear some of those M4A songs. Any ideas?