Forge 36.2.31

Optifine 1.16.5 HD U G8

Framed Blocks 2.14.2

Framed Corner Slopes when placed in certain directions will render much darker than other blocks when running Optifine. Confirmed this only happens when Optifine is installed.

The variation I seem to be having the issue with is horizontal_bottom_left.

There is unfortunately nothing I can do about that. OptiFine forces the enableExperimentalLightPipeline config setting to be disabled while presumably not providing a comparable replacement for the light pipeline that is able to light these blocks properly.