I've stumbled onto something odd. A search reveals that from time to time during the past, people would make complaints about their Last Played field not updating, or showing "never played" when they thought it shouldn't. I never paid much attention to this, as I didn't make use of that field. I never saw anything definitive posted about it, and a review of the version history doesn't turn up anything salient.
I was experimenting with a new smartlist to report music I hadn't played in a while, and this of course uses the Last Played field. What I saw leads me to believe that there is, or at least was, something fishing going on with [Last Played].
I found that nearly two-thirds of my library, many thousands of files, is showing "never played". Not only do I know this is not correct, but it's impossible, and I have the data to back that up.
First, a few preliminaries: I do have some tracks I haven't actually played, but that amounts to only a few hundred. There are zero issues with permissions writing to disk, so don't waste time bringing that up. Plus, that tag is not set to be saved in the file anyway. I have Last Played dates in my library going back to 2012, which demonstrates continuity of data. Last Played for the last 15 months seems to be as it should. Prior to that, I see issues.
I don't save Last Played to tags, as I don't want to dirty a file for backup every time it is played.
It's my practice when I get new music to listen to it (shortly after acquisition), and rate it as I do so. I do not rate tracks without playing them. So every track that has been rated, has been played. I always perform this function directly on the HTPC, never in a client/server situation. Sometimes when I do this, I am using JRemote to control the HTPC playback. Sometimes when I do this, I do the actual rating on JRemote, but I always look afterwards to ensure that that MC has recognized the JRemote ratings, and I never have problems with that. There is no streaming or DLNA. This is all local playback on the MC machine, from its own library on a local disk.
So I have all these tracks that show a Date Acquired (a custom field), and also show a Rating and a Date First Rated, but shows never played. Impossible. I also see, by the way, the evidence of the [Date First Rated] issue that Roderick previously reported, where that field was not being updated properly.
There definitely is, or at least was, an issue with Last Played. I wonder if there is an issue where this data is not restored properly and is instead cleared during a library restore (when the data would have been in the library backup). I have not done a library restore in the last year, so this might be consistent with what I'm seeing. However that doesn't explain why I still have some Last Played data going back as far as 2012.
Unfortunately I can't narrow it down more than that, other than to establish that it's a real thing.
I was thinking of alleviating the annoyance of all those "never played" tracks by simply setting the last played to = date first rated. But MC does not allow setting the Last Played field. I could also restore a backup from 2018 to see the then-recent last played data, but since I'm not aware of a way to reintegrate that data into the current database, I'm not sure it would be worthwhile. Although it could probably be done with data fiddler; I may try that.
Anyway I'm not sure how helpful this is, but I wanted to post it as corroboration for others who had experienced the issue.