Glowing effect stays on screen

When I used the command to give the villagers in the village I was building the glowing effect to get a quick head count, the outline of the mobs stays on my screen, in the position of the mobs when I gave the effect, even when I look away. This persisted even after I removed to effect from the mobs. The only way to get rid of the lingering images of the effects is to exit and re-enter the world.