Strange world flashing after relogging (death & effects with command blocks)

First time I encountered it was with a command block, which I used to give all entities glow... I expected was that it would wreck the world, but I hoped it wouldn't... What actually happened was that I wrecked the world

Second time, it happened differently. I was playing in survival and I got blown up by a creeper while fighting a skeleton. When I respawned the skeleton and items were invisible. Not the main problem, but cause I wanted to see the stuff again, I relogged. It worked. But then the world started flashing just as it did with the effect. The world start flashing weirdly and the world is forever lost, cause it wont get back to normal. New ones or untouched worlds still work.

What I expected from that was that I'd respawn and see the skeleton again, which it didn't. I had to relog and when I relogged I hope it would be fixed and the world wouldn't flash.

Steps to Reproduce - well, I made a video on how I recreated it for me.
https://youtu.be/9m5-o-Gkcuc