what bridge ?? you talking about webs or what?
Yes, the bridge made of web. The one closest to the blacksmith's room. Just past the broken wall.
ok AI doesn't like hazardous terrain maybe it's because of that. I had cases where Ai would just not go into those, be it webs or fire...
Anyway in this case it could make sense they are just protecting thier lair/eggs and don't want to leave them... We can call them territorial, if it helps.
But it's probably just a bug and AI spazzed out on you.