OS X here, not iOS.
Client has 2 MDMs: Casper Suite for OS X and Meraki for iOS. Client also recently enrolled in DEP.
I imaged a new Mac, but started getting prompts to enroll in their MDM (Meraki). No, don't want to do that. Had the client log into deploy.apple.com, add in a second MDM server and migrate that serial number to the secondary server. However, each time a user logs in, they are prompted to enroll in Meraki MDM.
I ran into a similar issue last year with iOS MDM (except it was a misconfigured URL). Once I fixed it, iOS devices still kept prompting to enroll with the misconfigured URL until they are wiped.
I don't want to wipe-and-reload this Mac... there has to be a way to flush/purged the cached MDM server information.
I've opened a ticket with JAMF Support but thought I would run this past the community. If JAMF provides me with a solution, I'll share it in this thread.
--Robert