Sounds like you might be triggering Blizzard’s new code to detect people trying to exploit the reset mechanic. I wouldn’t be surprised (and find it humorous) if they did something like once a boss is engaged, that is the only boss to trigger the reset until a full wipe or that boss is killed.
I also have no idea how you accidentally pull Freya but don’t want to actually kill her? Auriaya I can understand a little more about an accidental pull… but again why not just kill her?