[PlasmaKrab]

I didn't do any test on that, but I'm beginning to wonder if it isn't smothing related to the way soft vehicles are dealt damage (any damage).

Try firing against trucks or such with a tank or any heavy direct-fire weapon, and you'll have chances of seeing the truck losing crew members, but still technically running between two shots.

Just my 2c, I don't know if there is any relation with what you saw. If there is, you may want to check non-lethal damage done to the trucks, maybe several of them are technically "ready" but have suffered several damage points.

P.S. just another idea popping up: how about unit size? Tanks tend to have a high size ratio, and seeing how cluster rounds work, I'd find totally logical that 'smaller' units get less hits.