Reported: Generators and charms do not stack; each one takes its own bag slot.
Found: Generators and charms are stackable items, but every one of them is also a timed item: its timer starts when it is bought or granted, so two bought at different moments carry different expiry times. A stack merge is allowed onto a stack that expires no later than the one being moved, so the newer charm can be dropped onto the older one, but not the other way round, and the game itself may refuse the drag before asking the server.
Needed:
- The exact item name, and whether the copies came from one purchase or several.
- What happened when you dragged one onto another: nothing, an on-screen message (its exact text), or a server log line starting "stack merge refused".