@Greg Arnold, Thanks for posting in Q&A.
Based on my research, A device is considered active and will appear in the Work from anywhere report if it has uploaded at least one Endpoint analytics event, such as a boot, sign-in, or application crash event, in the past 29 days.
https://learn.microsoft.com/en-us/mem/analytics/work-from-anywhere#bkmk_score
Please check if there's any Endpoint analytics event in the portal.
Hope it can help.
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