I am going to move this to suggestions. This is not a bug as the event/item/sP that you get is random (except for the rift specific items that you get for throwing in certain items) and so it will always pull from a random list of possibilities. This includes the rift skin just like you can zap a human skin more than once during morostide.

However, it may be possible to change that so that is the reason I am moving it!