DIAGNOSIS Yeah, this one's common. The self-clean cycle isn't magic; it's basically just running the roller under clean water. If your floors were really dirty or you've got pet hair, it often can't keep up.
FIX After the self-clean cycle finishes, you still need to manually intervene. Pull the roller out (press the yellow tab on the brush roll cover). Use scissors or the included cleaning tool to cut and pull off hair wrapped around the ends. Rinse the roller under a tap and let it dry completely before reinstalling.
IF THAT DIDN'T WORK If the roller seems to be spinning slowly even during self-clean, check the intake channel right behind the roller for a dense clog of mud and hair. A long, narrow tool (a chopstick works) can clear it out.
HEADS UP Don't put the roller assembly in the dishwasher or submerge the motorized end. You'll kill the bearings. Just rinse the brush strip and plastic frame.