Hi @Tom Sweet Thanks for posting in our Q&A.
Firstly, Check Intune -> Devices -> Azure AD devices
"Join Type" make sure that it shows up as "Azure AD joined" instead of "Azure AD registered".
You'll need a Microsoft Intune environment, with Intune managed and Azure AD joined Windows 10 and Windows 11 devices. As documented here:
https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/configure-conditional-access?view=o365-worldwide
Please try to run a test detection for Defender ATP for any of the machines experiencing this issue. See:
https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/run-detection-test?view=o365-worldwide
Hope the above workaround can help.
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