Help with custom fur thickness for horses

Hello! I followed the custom fur thickness tutorial from h-emera on tumblr and i’ve run into a problem. I can’t figure out why but the head and feet of the Horse get all wobbly and wonky (as seen in the picture) also the mane and forelock get distorted. I only edited the lrle image and did nothing to the specular and normal map... maybe someone here can help me out? 



Here is the Link to the .package file:

drive.google.com/drive/folders/1hBeWvb-tzwnN_kNUkEiymRcB60Gv6gQD?usp=sharing