Simple issue, turning RenderArms to False does not work, arms will still render regardless when picking up an item, and as I have a modpack that changes some player animations, rendering the extra arms causes players to have 3 arms when carrying an item, so I'd need to disable this feature.

Fixed in next release. If the mod that you were having trouble with is obfuscate, you can leave renderArms on, as there is a fix for that in the next update.