NeoForge 21.1.172
Brewin' And Chewin' 4.3.0+1.21.1-neoforge
Distant Horizons 2.3.2-b-1.21.1
BSL 10.0

Basically causes Distant Horizons LODs to move out of place and across the screen, appear sideways etc. Works normally without Shaders on aside from a vanilla cloud render issue.

Honestly, I don't really know how this could be fixable.

I just don't seem to have enough knowledge in this area to actually know how this could be fixed.

From what I can tell the LOD's and Shaders themselves are maintaining its position, unaffected by the sway itself. But only rendered chunks appear to have a sway to them. I am not sure how you are implementing your camera sway but as much as I know how much it sucks, I would maybe take a different approach to it. A mod that does some camera manipulation that I know works well with DH is https://github.com/Mirsario/Minecraft-CameraOverhaul if you want to check that out.

A different approach to it is probably necessary, although I just don't really have the energy to do that right now. So I think you'll have to wait for a bit.