Same in our environment with 4.2.3.
Very annoying when you have a new baselayer and have to wait till next day.
It seem the process has very low piority.
That's right, it add a one day delay before we can test base line deployment !
can I ask is this singular volume you are working with or multiple volumes.
I know this is way after the original post, but I am seeing this for the first time. We are using multiple volumes. I am allowing Mirage to automatically select the volume as to where it wants to put things (which I have not done before). It appears that the Base Layer I am using is on our Volume 2. I don't know where it selected to put the new CVD that I am applying the Base Layer Provisioning to, but is the multiple volumes why it is "cloning" the layer, to a different volume?