With both the C90 and O-200 engine aircraft I had taxiing on damp grass almost required carb heat - otherwise the engines would go all 'lumpy' and die. Carb ice at near idle.
I've had a similar 'conversation' with a friend whilst flying my Terrier (Gypsy powered) - when he commented I should have removed the carb heat on short finals. So I did as we taxied back to the hangar - and luckily(?) it then went all lumpy - until I re-applied carb heat.
Granted the humidity on the ground close to grass will always be higher but it does illustrate the point quite well. But my friends O-320 never suffered from these issues.....