Using OS v2.1.2 on Arch Linux:
If I have two variants of a song, and choose to link them together (so song 334 is linked to 334a, and 334a is linked to 334) then trying to load either variant causes a stack overflow.
I suspect that it's trying to load each linked song recursively, and getting into an infinite loop, because it's not recognising the songs which are already loaded.
Anonymous