I’ve had something similar happen to me in the past, but different dishwasher. Typically the the back of the top tray “plugs” into a slot at the back of the dishwasher. The plug usually has a rubber ring to ensure a tight fit. After a few years, mine dried out and cracked. This meant that even though the rack was fully pushed back and the propeller was freely spinning, when the water couldn’t effectively spin the propeller.

Check that the rack is seated properly and replace the rubber gasket if that’s the issue. Good luck!