The DRC checker runs too slowly to run it after every pour, so it runs in the background. When things are working correctly, it eventually catches up. This can take many minutes on our design, which is only 5x5cm.
Sometimes things don't work correctly, and the DRC checker thinks it is up to date, when it isn't. When a bogus constraint violation is still there the next day, I know it will never go away on its own. These would go away eventually when I swapped one of the involved parts with an identical part or delete a via, and put an identical one back. I suspect any change to the design in the area of the nagging overlay would work, but I've been doing the swap a part with its self. Then I would exit the tool, and see if the nagging constraint violation was still there. If it was, I would wait half an hour, and try the exit upverter and restart. Then the problem would be gone.
Some bug trained me to delete vias and create new ones, rather than to just move vias. I've forgotten what the bug was, but it didn't happen very often, but when it did, it was a pain. Well more than 95% of the time, moving vias just works. I think it involved accidentally connecting nets. If a via touched the wrong net or pour while it was being moved, sometimes the tool would not forget, even after the via wasn't touching the net.