Animation Deformity Not working Right

I was making my animations and following this tutorial: https://www.youtube.com/watch?time_continue=749&v=gFf5eGCjUUg&feature=emb_logo and I finished the animation and moved on to making the clothes for the character by going into edit mode, duplicating the area of the character I wanted to be clothing, scaled it up, and separated it. Then I played back the animation and for some reason the hips started to shrink while the animation was playing. Does anyone know how to fix this without me having to completely reanimate him?