When a device is moved to a different policy, why does it still appear in the original policy's MDM Devices list?
When a device is moved to another policy, the device will receive all of the Catalog items in its new policy. The one item that will not change is the push certificate topic, which is why the device record will continue to appear in the MDM Devices list of the original policy.
What happens if I delete the policy the device was originally enrolled in?
Once you delete the policy that the device was originally enrolled in, the device will no longer show under the "MDM Devices" list in any policy. This will mean that you cannot perform audits from this page. However, with our recent release, you can now perform re-scans from GoLive: How to Manually Perform Device Audits.
Regarding functionality, the device will still communicate with the MDM server, as long as the enrollment certificate is valid. You can check device certificate usage in Addigy by checking out our article How to Delete Apple Push Certificates from Addigy.