Hi: There is a detailed article on facebook dealing with this problem. It requires removing the outer cover of the door sill (water may pour out) and notching it to match the actual drain hole in the sill. Simple solution. Don't understand why BMW hasn't notched the sills at the factory! I have a 2021 430i convertible and don't know if my car has the same problem. I have to lay down on the ground and check. The sill cover notch has to line up with the drain in the sill.