2016-01-24-1546-27.flv (sorry for the beginning part of the video, accidentally switched out of the game).
Couldn't make them destroy the doors w/o dropping ranged fighters, they kept going in circles for 3 mins.
I was able to reproduce that behaviour.
And it is rather complicated.
I was only able to reproduce the behaviour for the following units:
Gnarling, Augre, Beastmaster and Chunder (all other units didnt do the long march between the gates)
It is true for all gates except the glacial door, where it worked totally fine with all units.
in addition, it happened not in 100% of all tries, but only like 90%, while gnarlings tend to bug out like this more often than Augres, chunders or Beasmasters (those 3 will attack the doors from time to time, while gnarls just run around)
it is not related to the state of the door, so it doesnt matter if its open or closed or ai controlled on the editor.
It is caused by a few abilities using the same target selection method.
The problem is it tries to find a good spot to deal aoe damage based on the average center of nearby enemies.
This works in most cases but causes problems if all enemies nearby are equidistant to one center point, like here with 2 doors.
We are going to change this algorithm to use a median, so that it always picks a valid enemy location and not an average location which might be in the middle of but not even near to enemies.