Maps not opening new atlas nodes

I'm doing some mapping, going from tower to tower, and I'm suddenly stuck because my completed maps aren't opening the areas around them. I double and triple checked, there's definitely a line connecting the two maps, the previous map is definitely "Completed", but the map ahead of it is still greyed out.

I had that happen yesterady. But the game let me put another waystone into the map and let me do that map again.