After V12 Upgrades my default Media Library is changed

I maintain my media library (and related iTunes files) on a NAS. Until recently, upgrades never had an issue maintaining that linkage. Recent upgrades now change the library to the default Windows location... which is empty. I know how to repoint iTunes (Shift + Click) to the right library, but this new behavior is a waste of time. Would be nice to know what changed and if there's anyway to ensure upgrades don't keep resetting the library location.