Hi I'm one of the Galacticraft developers.

We have had to code around an issue where your custom RenderPlayer, RenderSubPlayer, is not preserving in that Java object the layerRenderers field from the original RenderPlayer object. Please see micdoodle8/Galacticraft@e8d0fae

I hope our workaround will work OK, but it is not future-proof if you ever decide to change the original field in this class - if you make a future change and you remember this issue, I'd really appreciate a heads-up for the change.

I'm also not sure what will happen when Minecraft calls .applyRotations() on your RenderSubPlayer object - it looks like that probably won't call our code where it should. Please can I suggest that you should override that method like this:

@Override
protected void applyRotations(AbstractClientPlayer abstractClientPlayer, float par2, float par3, float par4)
{
    original.applyRotations();
}

We're using a somewhat older function name mapping where applyRotations is instead named rotateCorpse, so your code suggestion beneath the horizontal rule is effectively already in use.

Take a look at this code and let me know if it alleviates the first problem:
#182

Thanks guys! 👍

Thanks @asanetargoss , makes total sense.
Your PR will help alleviate the first problem too, so thanks for that.