Exchange 2013 SP1 on Transport Service on Combined Role stops

We have Windows Server 2012 and Exchange 2013 SP1, the Roles are CAS and Mailbox in one box. My problem is when I create a custom Receive connector or edit a custom Send connector, the Transport service stops and mailfow is affected. 

What I do to resolve this is to disable the Receive connectors, restart the server, and enable the Receive connectors. 

Is this a bug?