Night vision potion effect has a blink effect some seconds before the potion ends.

When using beacons blocks edited by worlds editors with the night vision effect, when the effect is active, it will blink forever.

It could be fixed by having an undefinite duration ( long and hidden ) as you are in the effect zone of the beacon block, then it will back to 8 seconds if you are out of any beacon effect zone for that power ( with that it will warn the player that he's out of the area ).