I also have noticed this with path finding movement and decided to use other behaviors (may not be possible in all situations)
I had a player move towards enemy on path finding movement and had an event for on collision to attack (since enemy was still moving I didn't want to wait for arrival and have them walk past each other). Sometimes it would "arrive" at the enemies origin but wouldn't be close enough to cause collision.
Also had zombies that were supposed to take a few steps at a time so it was path finding a small distance. Randomly it wouldn't move at all when it was supposed to. I could never trouble shoot it. I guess now I know it was "close enough" so didn't move at all.
I know this post doesn't help you but I am interested in any resolution as right now path finding movement is my last choice, unless there is an actual maze.