Ahah! I'm not so sure I like the current changes (yet).
I ran up that same scenario for a little testing. Took the one Axis infantry and attacked in a manner I felt similar to what Big Joe did. Got level-4 disruption, and during the withdrawal phase I got to see the kind of retreat pattern.
Take a clear look here, since we can not stop withdrawing in the red zones, there is only one spot available for us to do so, which is two hexes North of the AT unit. However... in Joe's image there are some hexes blocked by E-ZoC which would restrict movement towards that one hex.
But HOWEVER AGAIN, there should STILL BE a possible path to get to that hex, so why there was no retreat is interesting.
Also, I'm not quite thrilled with how retreats are handled. If I want, I can currently just move (one hex at a time) my unit into say, the #9 hex, and its movement will be haulted despite having still 11 MPs left. Also, if I move to the #7 & #7 again, hexes, despite I should have still 9 MPs left, again the game will pin my unit there and decide there is no other possibility to move. Hmmm!
There are also some other issues there that make me think a bit...
don't let Tiger-I's