http://bugs.winehq.org/show_bug.cgi?id=34122
--- Comment #18 from olelukoie olelukoie@mail.ru --- (In reply to Stefan Dösinger from comment #17)
The original description suggests that the load order depends on Steam writing the files in the correct order. What happens on Windows if the game directory is moved away and re-created by copying the files back manually in a non-alphabetical order?
Depends on FS you use. NTFS always sorts files/dirs alphabetically regardless of creation time. FAT seems to sort files in creation time order. So using NTFS you would not see any problem, and using FAT you should see the same error loading DLCs. (see my comment 9)