What you're seeing is jamfHelper that locks the screen immediately after imaging. You can add arguments to it to change the screen type and text. I don't have exactly what they are but they can be found in the forums.
As far as disabling it, our work around was to kill the process after the temp users logs in immediately after reimaging. The device then auto-enrolls via scripts we generated in house. Do do this a simple script was created for the image and added to the post enrollment process
#!/bin/sh
killall jamfHelper
exit 0
