Server version#: 1.27.1.5891
Further information on this. Having added another album in with an updated date, it appeared in the right place, so I went to an album that was (since whatever change brought about this issue) in the wrong place and edited it, and it moved into the right place. BUT just opening it for editing, and Saving it doesn’t work - you have to make an actual change, save it, then re-edit it to revert the change - there’s no way I’m doing that for everything that’s been broken by this!
Still, it seems newly added albums work correctly, but everything added before this change, with an edited “Originally Available” date, will likely be in the wrong place…