2005 BMW 325 Winshield washers

I just purchased a pre-owned 2005 BMW 325Xi - Within the first 1000 miles (Car now has 51K miles) something went wrong with the wipers - They operate corretly - meaning they wipe at all speeds and the rinse work) hen I shut them off they stop in the middle of the windshield - they do not return to the normal home position.

Any idea what could cause this problem?

ThanKS

Ron Thompson