Sprocket Adapter slippage

I've never seen that happen with a 'rag joint' Just kidding.

The sprocket adapters are a great advancement for motorized bicycles but fit and tightness are critical.
When it was installed and tightened, did the two halves touch or was there a small gap?

If they touch there's a good chance the adapter was slightly oversized for your hub. Slippage like yours isn't normal. And I concur, get a new rim. That one is toast.

Tom

Oddly the adapter manufacturers rarely, if ever, provide torque values for their products.

The adapters must be tightened sufficiently to prevent slipping and often that is tighter than the user makes them.

There have been previous discussions about 'how tight' should the fasteners be. Below is a metric torque value chart that might help anyone curious about how to properly tighten metric fasteners. Apply the torque based on the size fastener used to clamp the two halves together and the sprocket to the adapter fasteners as well. This is assuming the adpater maker used metric fasteners.

Tom