@MoTaar, Thanks for posting in Q&A. From your description, it seems you have added device into Autopilot device but the object isn't created in AAD. If there's any misunderstanding, feel free to let us know.
https://learn.microsoft.com/en-us/autopilot/add-devices#add-devices
Based on my experience, when the device is registered into Autopilot, Intune will sync it to Device Directory service, and then it will trigger Device Registration Service to create the object in AAD. For our issue, please check if there's any previous device recorded related with this affected device in both Intune and AAD. If yes, remove the previous one.
Meanwhile, check your Tenant status to see if it is healthy now and if there's any related issue in your environment.
https://learn.microsoft.com/en-us/mem/intune/fundamentals/tenant-status
Remove the previous added device record and add it again to see if it can create the object in AAD. Add other device into Autopilot device to see if the AAD object can create.
Please try the above suggestion and if there's any update, feel free to let us know.
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