On discovery of
NEXUS-10421, I went back to all formats and made sure they were able to pull components being proxied with no connection to the internet.
Rubygems did not and gave me the following:
There were no pertinent messages I saw in nexus.log in default levels but I am attaching my log in case I missed something.
Should be reproducable or if I can get more info, let me know what. All I did was prime my NXRM instance with the nexus gem by installing it (verifying in repository browse UI) and then uninstalled it. Then I turned off my wireless and executed the above. When I restored my wireless it worked.
Rubygems was (re)implemented with 3.1 so no older NX3 check is possible. I did not check NX2 at this time.
I just upgraded to rubygems (command line tool) 2.4.8 today.