CD is having several tracks removed - after a few hours

I’ve been using Roon for 6 months+ with few problems. But this one has me stumped…

I put a CD rip (FLAC) of a CD, “This mortal coil, Dust and Guitars”. Roon correctly identifes the CD with all 10 tracks. I can play all tracks and know that there’s no problem with any of the files. Roon even analyses the tracks OK. Using a metadata editor I can see that the artist, track #, album name, etc, tags are all correct. The file names are logical and consistent, eg

02 This Mortal Coil - Song to the Siren.flac

But what happens is the next day or a few hours later, the CD seems to be replaced with a copy that only has tracks 1,3,5,6,9 and 10 (so it’s removed 4 tracks). The CD on tidal has 10 tracks. Last night I left the CD on the screen with 10 tracks, and this morning it says “This album has been deleted” or something similar. And there’s this new version with 6 tracks

I’ve tried this using roon-managed or unmanaged storage, local or network discs, get the same result each time.

Really puzzled…

PS System is a NUC-type PC, Windows 10, with most music on a remote PC share. Been working fine for months.

Is it just this album or do others share the same symptoms ?