I've now had two albums "disappear" in MC after changing their title.
I can find the files in the file system (Windows Explorer), and I can use the import tool to re-import them, but when I try that nothing happens, the album still doesn't appear in any searches but there's no error message. It does say "0 new files imported" so the albums are in the MC database somewhere but the various queries to find them don't include them in the result.
The two missing albums are Freddie King Taking Care of Business disc 1 and Bud Powell Birdland disc 3. There may be others.