Honestly, I've never had this problem. A lot of people seem to have, but my vehicles always seem to do exactly what I want. It's the MGs that respond horribly for me.
I have my tank decided to drive right into a house, drive around a fricking stone on a straight flat road or get stuck on a tree like a cat.
while my friend's MG will decide to reload everytime he deploys it and sometimes the arc is not as exact as he ordered it (he claims to be)