Easel not cleaning out pocket

Hello All.
First timer here. I’ve just completed my first cut using easel. The ‘clear out pocket’ tool works perfectly at 3.5mm on a large radius pocket but when I try a small area clean out at 4mm I get a rough bottom finish. Cutter seems to be ramping into the cut rather than staying at depth. Doesn’t complete with a finishing pass. Any ideas how to fix ?

Thanks in advance