Break up cape from donator shop is being buggy right now. Was working fine since I purchased it over a month ago. Currently the problems are: (sometimes)not showing on character when equipped (sometimes) when unequipped it doesn't show in inventory but will show in inventory in the cash shop.
This sounds like you may have had an img and wz installation in the same folder. Tested on both setups just now, no issues. Feel free to update us if you run into this issue again. Edit: Upon further investigation, it seems that the cape acts like an 'effect', which can be overwritten by other equips. This however, is not a bug, unfortunately. To convert it to a 'normal' cape would probably be hours worth of work.