It seems to me that the old vehicles running to buildings bug is back, I remember when SSI put out a patch to repair that since it is quite unlikely that a tank/track driver would intentionally run over a building and disable his vehicle on purpose.
On a couple of occassions I have had units disable themselves by running over buildings while selecting a path to the target hex.
I've have that happen before to,good way to get around it is move the vehicle shorter distances instead of just clicking on the final place you want it.This way you can control where the vehicle goes better.
Another thing to check for are "Tank Traps" as we used to call them. It's a raod or trail that leads through a building. To an AI that is the quickest route.
Watch out for a similar thing with helos that will fly over the enemy as the shortest route.
I just had a helo retreat off screen with a full load after taking ground fire.
Also, riverine craft will "collapse" buildings on the waters edge, although I have not had one get stuck yet doing so. But as noted above, if you move 1 hex at a time, which is prudent anyway, then you avoid that problem.