So I'm trying to make a Ukulele for sims to use as an accessory with poses. The mesh is really just the original guitar from the base game, but since that one has a cutaway (one of the top sides isn't rounded), I had to adjust some vertices to make it rounded like in the picture. However when I import the new mesh back into workshop with the same textures as the original mesh, that selected in the red box happens. I though it must be a problem with the UV's, is it right? I redid all the UV's and tried it then in game, but when I go into the accessories tab in CAS, the game crashes. Do I need to change the UV's like I did? Or is it rather a problem with having to change the multiplier or the clothing specular?
Thanks in advance

it has to do with the UVcoordinates or maybe a missing jointassignement.
Check if any coordinates are to close to the edge of the map, it usually gives distortions like this.
Check boneassignements on that area.

Thanks Blooms, I'll take a look at it!!!