I am sorry I missed this reply. Yes we did figure out one cause. Our scripts were using a lot of variables as members to another device. E.g.
var MyTeleporter : teleporter_device = teleporter_device {}
We would then resolve these with tags later to get the real device we were looking for. We did not realize that this also created a default version of the device and I am guess that the Prepare set goes through the verse scripts and creates these devices on Preparing. This step was mostly unnoticeable until we had a custom device with a number of these member variables and then places a few hundred of this device.
The solution was to do something like this to prevent the default device from getting created.
var MyTeleporter : ?teleporter_device = false
Hope that helps.