So we're running in to an interesting situation here. We are running a pretty large multisite network - we have both Domain Mapping and Jetpack installed. We were having a lot of trouble getting Jetpack's Publicize module to work but we found that manually setting the server port to 443 made it work - so adding this to wp-config:
/** Use new port for jetpack HTTPS **/
/** $_SERVER['SERVER_PORT'] = 443; **/
This will allow publicize to work, however it breaks any site that is using domain mapping and doesn't have their own SSL certificate, as it seems to basically force SSL on the front end.
Anyone run in to this before or have any ideas?