As the title says, if you enable PBR, the entire Shader pipeline crashes. Causing shaders to turn off completely and be unable to be reenabled.

Shaders in Minecraft are used to render realistic graphics. Once activated, the shaders take over the rendering of water, environment, lights, and other graphical elements in this game. You can find ...

If textures have a FabricSkyboxes custom skybox, Complementary shaders cause the skybox to go completely white; rather than showing the correct setting toggle for either the custom or shader skybox.