Minotaur Rockslide Circle "Turning off" when not in circle

I've had multiple attempts against the Guardian of the Minotaur now where the falling rock circles will be completely invisible until I walk in them. After running into this a few times I also found that minions and totems will not take any damage while within the circle unless it is visible, and that it appears to last longer than ones that are always visible. This indicates that they're not just failing to render but that they're actually "turning off" when the player is outside the circle and then turning back on when the player is inside, keeping whatever duration it still had.