I'm not sure what is happening here:
https://i.imgur.com/WiNx2IF.png
another example:
https://i.imgur.com/b7jOA2G.png

Made no changes to CC4 Kevin except added beard, 
Double clicked on "Basic T-shirts" and the neck looks messed up.
This seems to happen with other shirts as well.

Doing "Transfer Skin Weights" makes it even worse.
Not sure what I'm doing wrong here.