Not so uncommon when an AT gun is placed in a location which a vehicle can reach and the mechanic you saw was the equivalent of an overrun. Just don't try it against a gun located in woods, forest or rough terrain as the game knows the approaching vehicle can't possibly enter the defending units location. Usually ends with a dead vehicle.
Regards
vR
it was strange to see, as long as the vehicle was static the gun kept on turning...the moment the vehicle (which was very close) started to move the gun surrendered
during the turning my vehicle did not consider the gun as lethal since it didn't fire or put any LOF on the gun
