I've had this problem occur intermittently for CD rips in MC 23 Builds > 73 (64-bit). I have experienced this problem as an intermittent bug that affects Flac rips, and presumably any other format. I've experienced it as a more general problem with MC tag editor info intermittently not being reflected in the ripped CD tracks.
When the problem occurs after ripping a CD, the metatag info looks fine when viewed in MC on the machine used to rip the tracks, but just isn't there if examined on the same computer in Windows Explorer. Track names etc., apparently are not actually being updated in Explorer according to the values set in the MC tag editor (e.g., no artist/author name will appear in the Explorer file properties even if they were entered in the tag editor prior to ripping, and tracks are not named in Explorer according to MCs settings - my setting is [Disc #]-[Track #] [Name]) - tracks are instead named 01Name, 02Name, etc..
Unless you look in Explorer at the files after ripping, you wouldn't know - the track metadata info looks normal in MC running on the machine on which they were ripped. But if examined in Explorer or imported into the library of another machine running the same Build of MC, the absence of expected tag info is apparent. Also when this occurs, if examined in the MC tag editor on the second computer, all tracks are numbered the same (e.g. every track has "1" as the value in the [Track #] field).
It doesn't seem to affect the ability to edit and update existing tracks - there the MC tag editor works fine and changes in tags are updated in the Explorer file names using Library Tools/Rename, Move & Copy Files as expected.
But when it does intermittently occur on CD rips, it results in the effort put into to trying to edit the tags in MC prior to ripping having been a waste of time. Instead, it seems one has to manually correct the info in the MC tag editor on the second machine and then rename them as desired through Library Tools/Rename, Move & Copy Files.
I really hope someone will fix this.