Particles (or atleast the Nether gray particles) become thin when looked through a Spyglass. Its a visual bug and not very urgent, but it is something.
MCPE-137733
Particles become thin when looking in a spyglass
Open
5
(Unassigned)
588725
Confirmed
Windows
1.17.30.20 Beta, 1.17.10, 1.18.2 Hotfix
Retrieved
It's kinda like the particles face the opossite way they should. Anyways, affects 1.18.2