@Jon Resele, Thanks for posting in Q&A. In general, the steps to remove Autopilot devices are as below:
- Remove the devices from Intune.
- Remove the devices from Autopilot devices.
- Remove the device from Microsoft Entra ID.
Note: Non-Microsoft link, just for the reference.
But from your description, it seems the device is still unable to delete after we remove the Autopilot device. Please ensure the devices under Devices in Intune portal is also removed. Wait for some time for sync to see if the result will be different.
However, if it is still not working. please open case to help to remove the device records.
https://learn.microsoft.com/en-us/entra/fundamentals/how-to-get-support
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