at org.spongepowered.asm.mixin.transformer.PluginHandle.getMixins(PluginHandle.java:128) at org.spongepowered.asm.mixin.transformer.MixinConfig.postInitialise ...
OptiFine doesn't load textures, colormaps, or chunks correctly. Attached screenshots provide detail. On interaction, these chunks update and there will be no problem while you are inside the chunk.