Due to a bug where entering handjobmode with either hand will cause the original left forearm asset to reload and break the mod I've opted to just remove the left forearm. The reasoning for keeping the right is that unless you're looking for it, the size difference isn't too noticable.
If you want the original mod where both arms are thin, the previous version will still be available.
If anyone has any insight as to how to fix this issue please let me know!