I've noticed the clumping of grass problem that others have talked about, but mainly with very moist grass. I've studied the underside of the deck and believe 2 things are happening. First, the plastic easily scars from normal use, (micro etching), thus the moist grass can find spots on the deck to stick and more blades stick to the moist grass until the clump falls to the ground. The circulation under the desk seems good, nice "Oval" shape for the air to move. Would a smooth coating on the bottom of the deck prevent some of the clumping? Maybe a Teflon (or something more durable)? I've modified my blade to stop the problem, but the OEM blade does exhibit this issue.