When I am receiving a status effect from a beacon, it is constantly blinking on the HUD as if it were about to run out. However, beacons provide their effects continuously as long as the player stays within range of the beacon.
I presume that the cause of this bug is that beacons provide 8 seconds of their effects every 4 seconds. Changing this to a proper continuous effect would also fix the issue where beacon effects randomly run out and restart when there is high tick lag.
Update: as of 15w36c, the effects in the HUD also randomly reorder themselves every 4 seconds.