I have a Maytronics Sprite utilizing NastyBags. The robot works great most of the time BUT after it's 2.5 hour clean at night, it sits on the bottom of the pool. If I go to restart it, I get a plume of dirt out the top exhaust for about 5 seconds upon restart. This also happened with the cloth bag that came with the unit. Here in AZ it's very dusty and alot of fine particulate ends up i the pool. Has anyone else experienced this issue and suggestions?