The replication pauses when you add a new disk to the source virtual machine.
When you add a new disk to the source VM and you have disabled the automatic replication of new disks, the replication pauses.
vSphere Replication detects the addition of a disk to a VM and generates an event such as vSphere Replication handled a disk addition on a virtual machine.
Include or exclude the new disk in the replication.
You can set up and view an alarm for the event by using the vSphere Web Client. See the vSphere Administration with the vSphere Client documentation for details.