Masterpiet98

Try adding something like distance or dx/dy/dz to the entity selector.

/execute in minecraft:the_nether as @e[type=minecraft:creeper,distance=0..] run say test

This one works for me. It executes only on creepers in the nether.

I agree with jredfox (25/Jul/18 3:23 AM) that the cross hair is just a symptome. The gui rendering has a problem and i would say that it's happaning while scaling the texture to the right size. I noticed while making the beacon gui texture for a ressourcepack that it looks weired ingame.
I attached the beacon gui texture and a screenshot of the part that rendered weired.

I've got the raising memory issue with my 1.13 client. Additionally every time the memory resets to a low memory usage, i get huge lag-spikes. It happens faster or slower in diffrent worlds. In some worlds this repeats every 5 seconds, in others every minute.