I am not sure if my issue is related or not, so for now I am adding it here.
My setup is: Minecraft 1.8, No mods at all except for: OptiFine_1.8.0_HD_U_D5 and no resource packs. Optifine is on it's default settings.
When I use "forge-1.8-11.14.3.1521" everything renders out just fine, but any version of Forge newer than 1521 gives a much! darker render to all 3D inventory blocks. See attached image.
I have read that forge did update their render engine thingy and that Optifine now needs to catch up. Is this still true?