Thomas… let’s drop once more a flag to @support
My Mac mini shuts down every night and I reboot it every day and… never seen this issue
wait… it actually happened here too once, with one multi-disc album, after updating to 1.3
found that album to be the one and only, in my whole library, to be splitted by disc in sub-folders
everything else, here, is organised by 1folder=1album so, usually, path is “music/File Format/Album” whilst for that one is “music/File Format/Album/Album Disc1” etc