We are seeing Macs enrolled in DEP not running the expected Splash Buddy and software install policies. My suspicion is the Smart Group the policies apply to is not updating before the enrollment completes and so the policies are not running. Wiping and re-doing the machine worked correctly.
The pre-stage we are using is our "default" in Jamf and the smart group the policies apply to are devices it applies to. This seems like an issue that must pop up with regularity—is there anything obvious we should be doing on our end to facilitate this process? For obvious reasons the initial out of the box setup is most important.