Broken Uv's ?

So a buddy of mine and Myself were both doing projects within unreal 5 characters to be exact but I had an issue where my uv’s were broken on some of the parts of my character when importing him in unreal. It was wierd since it worked in marmoset fine and i had just finished texturing the whole character in substance as well, He did not have this problem with his character he thought it could be the mit mapping but he had just messaged me today saying he had the exact same problem with his character that he was doing at work.

I’m just wondering has anyone else had this issue were all the uv’s are fine in marmoset maya and substance but some of them break when trying to apply them to certian peices within unreal and what could that be?

thanks and cheers