I had this same exact problem. I had to log completely out of the game and come back in to get them to be lit up again. It stopped me on the fourth one and then showed all of them out. I logged out and then back in and they were all lit up again so I could get the next two.
I had the same thing happen with lighting the watchtowers in a future quest where it only allowed me to light two of them but not the third. I logged completely out and came back in and it allowed me to light the third.
