Bug with Demon Vessel event

PC Bug Report
1

Cannot interact with the last prisoner to free him.

Screenshot below. There was no highlight around the prisoner. There was only a few seconds left for the event and I was completely baffled so couldn’t take screenshot earlier. This was done just as the last second passed
https://imgur.com/Ux1tgC0

2

3

This event bugs frequently and I was able to achieve perfect once out of maybe total of 3 tries. I can’t remember what I did exactly to achieve a perfect one.