Command Argument r=,rm will detect entity at different dimensions

When a player standing at the center of the world x=0, z=0, and execute the command: testfor @a[r=20], it will also detect the players that is near the x=0, z=0 in end dimension.

How to do the bug:

put a repeating command block at the over world x=0, y=100, z=0, inside put this command /title @a[r=20] actionbar test

this will show you the test text when you are close to the location of the command block

then stand on top of the command block and do /tickingarea add ~ ~ ~ ~ ~ ~ test, this will keep the command block running even the chunk is not loaded

and now go to the exact same coordinates but in the end dimension, you can still see the test text on your screen, this means the command block still think you are in the range of it even though you are at another dimension.