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.