Old music appears in Recently Added

So far, my Apple Music experience has been quite good, syncing with 4 devices (2 Macs, iPhone, iPad). But on the Mac, I note that under "Recently Added", old albums from my library keep appearing. They are unchanged, but for some reason they are considered "new". So far, they are all albums that I ripped from CDs, not iTunes Store downloads.

These albums do NOT appear under "Recently Added" on my iOS devices, though in all other respects the sync of songs and playlists appears to work 100%.

This is obviously not a huge problem for me, but I am curious to see if others have observed it. My library is modest, about 25,000 tracks.