Spawning structure_void blocks randomly in anient cities

I was playing and searching for bugs on warden or anient cities normaly.

After i found that sometimes i break invisbile blocks in random places.

So i found one of those weird invisbile blocks and i got a sturcture void from commands
and i found it 1 to 3 of them in random places.

So i think this is illegal so i repoted and hope that helps u.

Sorry if i didn't put a screen shot my wifi is weak.