All of the sites use a Sucuri plugin which monitors and hardens the site against security threats. I have had several reports and have witnessed myself that editing the sites are slower than normal, and you may see an error like this:
Sucuri: (1452076628) Send_log: SSL connect error.
This message is indicating that a message was sent to a site that logs activity on your site. When you edit something, I generally get a message to indicate at a high level that something has happened on the site. 99.999% of the time it is normal activity, so I dismiss the items. It is this function that does not seem to be working predictably.
If you site is slow to respond to editing, and/ or you see a message from Sucuri, then go to the Plugins menu item. Locate the item (see image below) and temporarily deactivate it.
This will stop the problem from occurring. When you have finished your editing turn it back on.
I am making enquiries about this currently, it could be something in the hosting that has changed, or something in the plugin (a bug) that has recently been introduced, or something at the hosting service that Sucuri is managing that is collecting all of the messages that is not working. If it continues to be unresolved I will eventually remove it. Right now I would prefer to keep it on the sites as it is one of several valuable sources of security information about your site that I receive.
(Update 11:50am 6th Jan 2016)
Sucuri are aware of the problem and are planning a fix. It should be out shortly (next 5 days). There is a workaround that they are suggesting, but for simplicities sake, recommend that you deactivate it when you are editing and turn it back on when you log out of the site. Once the update is published your site should be able to resolve the problem.