What happened

I was helping someone with a function and the function uses the /execute at command. When I try to run it in the nether or end, it ignores everthing unless it is in the overworld in which case it acts appropriatley

Strangeness

Strangely, when trying to reproduce with a different command, it absolutely not work, only with the command that I am using

How to reproduce

1. run minecraft in 18w11a
2. summon an armor stand named Control
3. teleport it into some blocks in the nether
4. run this command: /execute as @e[type=armor_stand,name=Control] at @s unless block ~ ~1.7 ~ air run say hi
5. you should see hi appear in chat
6. repeat steps 2 through 4 on the top of the nether
7. you won't see hi appear in chat unless something is acting very weird on my client

I have no clue why this happens, if you have any idea what can happen or if you can reproduce, please comment as such.