After freeing Marie-Louise and 'killing' one of the True Forms, the game sort-of freezes (still running, but stops responding to my input). This, I had find a way to work away, with saving-quitting-reloading. But, even though the game runs normal afterwards, I was never able to use Marie-Louise to hack anything.

Is there a trigger I miss, or is it still some bug?

(Edit: Apparantly there's also no 'Exit Door Controls' indicator and no skull symbol next to the table.)

Its a heavily scripted encounter and it changes slightly based on which doorway you entered from (via the kitchens or the main door between the two cannons, upstairs).

I entered by the Kitchens and it played out like this:

After the initial room clear, Marie-Louise cries out, you all run over and then _______ appears in the glass booth to gloat. Two bugs come out of the walls, Marie runs to the south side of the room and two more guys enter. Then she runs to the north server room and proceeds to do absolutely nothing.

You have to kill off the guys and the bugs, and have someone within sight of _______ in the glass booth.

Dialogue has to start with _______ after you expose the 'true form' of the bugs. You swing and miss on the spirit bugs and they raise up their dead flesh once more. It wasn't until the second time I made spirit bugs that Marie-Louise finally started her hack (and is added to your party list).

Two more jack points become active beside her. I found it a lot faster to run my player character over to her and do the job for her at this point (as I was a rigger/decker). Marie-Louise has to push the final button in the Matrix, though.

Once this is done you have to book it out the matrix and move your guys over to and out the exit.

I entered through the main door.

Everything plays out as you decribe it. But Marie-Louise was never added to my party, not even after I killed the bugs five times. And I'm no decker myself, so it's not an option to do it for her, either.

Ok.

I just reloaded a save from the Brotherhood upper floor and went down the path you did. It bugged out on me (no pun intended).

After freeing Marie-Louise, everyone gets moved to the booth and Grandmother J comes to talk. Two more minions enter from the south door, and two bugs from the north. Marie-Louise.... runs out of the southern door and it locks behind her!

After the first bug dies it can't be hit and reanimates its flesh... Grandmother J has another rant, the camera swings down to where I assume Marie-Louise is hiding, and then returns to combat mode. The quest says to use Marie-Louise to hack the exit (north, behind the bugs).

Only she can't because she's still locked behind the southern door. This didn't happen when I used the Kitchen doorway that's hidden behind the vending machine.

Marie-Louise did run around at the start of the fight, but she didn't exit the room or get stuck outside. She's supposed to run to the server room after everybody enters and equip her deck, you can see it lying on the table in there.