This bug is showcased on a YouTube video.
https://www.youtube.com/watch?v=mV6RGEdvwWU

What happened

Entities don't act normally (TNT don't explode, arrow act strange, sand don't fall, mobs don't spawn...) when a player enter The Nether from The End by the Nether portal.
Setting yourself to Survival mode causing some entity to reappear and work, but it the behavior is strange.
The bug can be "fixed" by relogging the game in Singleplayer or restarting the server in Multiplayer.
However, running /execute as @s in minecraft:the_nether run teleport ~ ~ ~ doesn't trigger this bug.

How to reproduce

1. Set yourself to creative mode.
2. Go to The End.
3. Run /setblock ^ ^ ^2 minecraft:nether_portal on The End.
4. Go inside the nether portal you just placed.
5. Attempting to explode TNT don't work (but with a sound), arrow act strange...