Running multi-network WP install. Using Apache with Nginx for caching. Activated JetPack on a single site. When I typed in credentials for connection to wordpress.com, I got a 502 Bad Gateway Nginx error. But, on returning to the site's dashboard, it is working, and there appear to be no untoward effects on the installation.
I can't release plugin this for our users to install until I know more about what causes this error and why it's happening. Is anyone else getting nginx errors with JetPack?