I'm at the part where there are the 3 pillars that activate the gates. I can manage to make it through the gates, but I can't find a lever/chain on the other side to disable the gates so the my follower can catch up with me.
Any help?

I just did that and Aranea managed to follow me through. I stayed close to the gates tho, and didn't charge forward

ye im pretty sure lydia just walked thru them

i remember going thru them and thinking "oh no, shes gonna get stuck" but she didnt.

so im not sure how to help other than reload, or just complete the rest of the dungeon and they will probably exit when u do