Quick win blog post time.
I noticed that some co-managed devices were not reporting back the Azure AD Device and Tenant ID information in the ConfigMgr console.
This information, for a device, is collected during a Heartbeat discovery. A quick check there and the setting was configured to its default setting of every 7 days. I changed the setting to run every day.
In the meantime, a run of the Discovery Data Collection Cycle action on a device will bring the data back into the console a bit quicker.
I hope this is of some use to you if you are in a similar situation.
SCCMentor - Paul Winstanley 
Should down-level devices like Windows Server 2012 R2, which have been Hybrid joined using the workplace join tool (autoworkplace.exe) show device IDs in the SCCM console? I have confirmed mine are in Azure AD, show a status of Hybrid Joined, and have a device ID.
And by ‘have a device ID’ I mean they show on in the Azure AD console, not in the SCCM console.