Hi,
Others have posted various UV issues with V8, so I won’t reiterate except to say something is definitely borked with UVs.
My new one to add to the pile is as follows.
If you ExtractMeshFaces in V8 the mapping on the extracted faces goes to the full UV domain.
In V7 it maintains its correct previous mapping
v8-extractmeshfaces_UV-bug.3dm (3.1 MB)