I'm very confused as to how and why I lost a

[Nappa]

The problem was the gate was NOT blocked by defenders. The earth mother was back and to the side. I purposesfully had many vine ogres in the army because they do lots more damage than carrion creatures which are great at immobilizing opponents.

About 50% of the defenders side of the gate got blocked by my creatures attacking the earth mother which was fatigued about 2 elephant lengths back from the gate. The rest tried to go around and appear to be stuck even though there appears to be a lot of space to move through. And actually having watched the replay again, they did initially move through and spread out and then simply stopped moving for the entire rest of the battle. No fatige, no spells, just stopped dead. I believe it is a pathing problem.

This is a bug, not a design issue.