Probably easier to just show this.
Missing Textures

Sodium kept showing white over all the textures, so I tried your mod, and got this.
Resource Pack Overgrowth

EDIT: I have a custom pack on, and and trying to figure out the issue with it. It seems to be the one causing the issue.
EDIT2: It also still does it with overgrown.
EDIT3: Using the 'Disable CTM' option lets me see the textures. But at that point, not connected.

Are you using Sodium? It happens to me when using this mod together with Sodium.

Do you have Indium installed?

Do you have Indium installed?

Indeed, Indium does fix this. Everything's working great now. Thanks!