Are you sure? How SSL and XML are related? I don’t see any relation here.
Do you see that error in the console only during merge or also while regular use of the forum?
I tried to reproduce by just navigating and BOOM I’ve seen one occurrence happening by just opening the admin interface, the response to the message-bus was triggering the XML parse failure was:
You’ve performed this action too many times. Please wait 1 minute before trying again.