Take a clothed CC4 character from CC4 and export to FBX. Modify clothing with shape keys in blender with no change to character. Export FBX from blender. Create character in CC4 using FBX from blender and using the FBX key. Character imports to CC4 with no problem. Send character with morphed clothing to iC8 from CC4 and partway through the transfer, iC8 crashes. I tried many different attempts all fail. If I save the morphed clothing in CC4 as custom then open iC8 and load the same CC4 character directly in iC8 and add the morphed clothing from content then the clothing morphs are there and work but the outer clothes remove the characters underwear and if you then add underwear, it removes the outer clothing.  I have done this many times using CC3 and iC7 with no issues. One thing I noticed while experimenting is that re-importing the character to CC4 from blender sometimes the outer clothing and underwear come back on wrong clothing layers (reversed). Sometimes the outer clothing comes back as hair. Correcting these layer issues on import doesn't help.