So i was asking the incapable AI to go somewhere while the Marshall was in water, and it ended up taking the vehicle to the shore. In the process, it got stuck on a "rock".

I took control and tried to wiggle free of the invisible barrier, took some time but it shouldn't happen. As you can see from the screen shots, it's not really stuck on anything visible. {F21585} {F21586} {F21587}