Using Optifine HD U7 (As of writing, the most updated version) and Epic Fight 18.1.16 (Also newest as of writing) results in the above issue where all blocks have extreme texture breakage.

Is this even involved with epicfight? I've never done anything with block textures.

Delete optifine config and it will fix this issue, this won't be fixxed now since optifine is not open source