How do you morph UV's? If I take 2 meshes with the same number of verts and different UVs, blendshape ignores the target UV and just stretches it. When you have text or a distinct pattern this looks awful.
In the image below I created the mesh (A), duplicated it and created a new UV (B) then created a blendshape from A to B. 2nd row (L) is the undesired stretched result which should look like the right side.