When loading a shader (Xilefian's BlusteryDay shader), it works as expected on 21w10a, with the trees and plants waving. However, if you load it on 21w13a, the shader has no effect, with the trees static and some log spam (log spam apparently MC-218831). 

Steps to Reproduce:

1) Load 21w10a with a supported GPU (not on warn list) and activate the BlusteryDay shader.
2) Load 21w13a with a supported GPU (not on warn list) and activate the BlusteryDay shader.

Observed Results:

The shader only functioned on 21w10a, with the trees properly waving, but on 21w13a nothing happened.

Expected Results:

The shader should have worked on both 21w10a and 21w13a