Strange things happening at a siege

[Graeme Dice]

Originally posted by Austen:
Are they hiding in the fort and I can't tell they are there?

That's exactly it. When you are sieging a fort, you can't tell what's inside.

I have even equipped 5 leaders with Gatecrushers.

If there are 1400 units in the fort, and a good portion of them aren't mindless (ghouls for example), then you will have a large amount of trouble breaking down the walls.