To help us look into this further, could you please provide us with a bit more information about when this occurred?
-Were you above or below the suggested level for the mission?
-Had you finished 'The False Oracle' quest?
-Do you remember if you tried speaking to the effected priest first or last while you were doing the mission?
Any extra information that you could provide would be greatly appreciated!
I'm sorry that i reply on this thread but i was having the same problem some hours ago and i can provide some footage.
Spoiler: Show
I free one priest (beginning the video) and then i killed Medunamun , after this i tracked this quest to finish and i could not free this priest ( 0:42 ) , but at the others i could. ( 1:57 , 2:24 )
To solve this issue i restart the quest , 4/5 free priests and this priest is changed and i could free him. ( 4:05 )