Items disappearing from catalog over time

I had an odd thing happen yesterday (may have been happening for some time, not sure).

I had listened to two new albums yesterday morning and went back to listen to them again, only to “find” they were missing :confused: Still on the hard drive in the watched directory, but no longer listed in Roon.

In fact, I noted a lot of tracks / albums were missing - I have just short of 90k tracks, and only about 80k were showing in the database. I tried forcing a rescan of my two watched directories, but it did nothing; i.e., no new items were found.

Rather than trying to troubleshoot, I exited Roon, deleted the database files, and started all over. After scanning all night, it appears “all” my albums are back (i.e., almost 90k tracks, 5455 albums), but I’m concerned this happened at all - how do I know all my albums are actually listed? How do I know they won’t disappear again, and what could be causing this?

Any thoughts?