EDIT: on further inspection, in the second example, while the filename was correct, the first parent folder name was "%albumartist%", so it seems to be a problem with whatever the first element of the string is (and in the case of it being just one, then that's also in a way the first). Tested if adding any non-variable elements before the first variable one fixed it, (like for example "A %filename%"), but it didn't, seems to be specifically an issue with the first variable element.