How to smooth card flip animation?

Hi, I’ve cloned and followed an excellent ‘card flip’ demo from @KevinBrand but while his flips back and forth smoothly mine jutters on mouse-over. Can someone tell me where I’m going wrong please?

Thanks

My share link is here, page is Dev
https://preview.webflow.com/preview/rjdeanplasterers?utm_medium=preview_link&utm_source=designer&utm_content=rjdeanplasterers&preview=b21c09046158232587e51f7b5e1076b9&pageId=5fbcf485cfb43b54fb5503f8&mode=preview


The clone of Kevin’s good work is here
https://preview.webflow.com/preview/flippin-cards?utm_medium=preview_link&utm_source=designer&utm_content=flippin-cards&preview=f0d3615cab2fdf0243261d6bf42a8731&mode=preview