I had a similar softlock in Skyrim at release that wasn’t fixed until the toolset came out and I was able to go in and see that the script that was meant to fire was never actually added to the trigger. So a dude is supposed to come up to a door and open a little window to talk to you, but he would just stay sitting down in the room since the script telling him to go to the door and begin the dialogue that leads to the trigger that opens the door was written and available, but wasn’t tied to the trigger of activating the door. I just put the script into the trigger and Bam! finally was able to get through the MQ.