I had a similar situation with an ostwind the other day. I dropped a 1000lb bomb directly on top of him. He was in the middle of the crater, and no damage, still firing. I dropped a second 1000lb bomb and placed it directly on my first crater (wow luck!), this time the ostwind exploded. I know there's issues with craters blocking tank rounds. In looking at craters from the ground, there is a definate 'object' above the ground, and depending on angle you can see the separation between the two (much like the turret of the tank and the superstructure). Maybe this could be causing problems with how some base objects are created/displayed over certain terrain features?