I have a habit of saving prior to the events that are irreversible in case I make a mistake. I did this with judging the mayor and went back to see if there was a better option. Only now it glitches, does not show the cut scene and does not let me make a judgement.
Move to another area outside of Skyhold then return.
Some cache data seems borked on quicksave.
I got this a few times too when saving just before a judgement and reloading the save file just after. But as the person before me says, go away a bit, open a few doors or run outside or something before reloading. That helps.
Thanks for the tip. I had the same issue with one prisoner that needed judging - will try to get this fixed again.
