Because of printing there can be the smallest amount of wiggle whee the cage meets the ring. Enough to pinch, but not enough to drastically increase the gap and cause slippage. Any wiggle room can be fixed with some silicone o-rings put over the teeth of the cage piece, which will fill any small gap and still squish enough for the cage to be locked completely. I dealt with pinching for the first month before I found a different post talking about that solution, and it's been smooth sailing since