@James M. Arthurs Thanks for posting in our Q&A.
For this issue, did you configure a device clean-up rule to clean devices or configure "add device to retire list" in actions for noncompliance? Based on my understanding, if they are not configured, the devices will not need to do re-enroll to intune.
Generally, we will configure "Compliance status validity period (days)" in Devices > Compliance policies > Compliance policy settings to specify a period in which devices must successfully report on all their received compliance policies. If a device fails to report its compliance status for a policy before the validity period expires, the device is treated as noncompliant.
When the device doesn't check in for a long time, the device will be marked as not compliant, and it will not be unenrolled from intune.
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