Thanks for this advice. I have rolled back al the way back to EC 1.6 and the issues with shutdown still exist. 
@jonathon.hall could this shutdown issue be unrelated to the EC? I am still happy to try to collect the logs with your instructions.
FYI - I have updated EC from 1.6 that I installed during debugging, to EC 1.11.
This is not a critical or urgent issue, but would be nice to at least understand why the shutdown is broken. Whatever attention you can give - I would appreciate. 