My world was made in 1.15 but it is a problem in 1.16. It's like the clouds become one with the build after they touch. I linked my video of how it works on my world but file size to big and can't fully show where it starts and stops without video
It's a circle tower 27 diameter I believe but it makes a rain x Ray from max height to my working floor but I have a ceiling of glass it goes through and smooth sandstone I'm sure it's a solid block glitch in general it only happens in the area that touches max height
https://youtu.be/PPuXBjYwF1E