This is at best a very edge issue for someone doing sync on a mac, but the old pre-osx/legacy 4-digit Type and Creator codes are (unsurprisingly) not synced. The vast majority of users syncing apple to apple aren't going to encounter this, but it is something to point out if some mac user with a legacy app is suddenly thinking they have corrupted files. Not surprising given that apple label/tags don't get synced either. Re-entering the appropriate codes for the affected file does fix the problem.