Compliance delays on pre-provisioned devices have been an ongoing issue for us. My own view of what is happening at least for us. We have had multiple cased open going back to early 2023.
Word on the street is updates are coming to Intune 2404 that will help alleviate some of the compliance delays on devices in error due to a transient state. I think the goal here was changes to the reporting of the transient state of the FW/AV components. Think SyncML500 errors.
Devices that are pre-provisioned and a delay occurs from user enrollments, think sitting for x days before enrollment, are impacted by the day 1 scheduled task not running every 3 minutes for 15 minutes / every 15min for 2 hours for syncing the device. These tasks are scheduled to run after enrollment but are created and started on the pre-provisioned day. When the user finishes the enrollment, they are not updated with the current date for the user enrollment so they don't seem to run any more to help get the device syncing and compliant like you would see on a user only enrollment.
\Microsoft\Windows\EnterpriseMgmt{enrollmentGUID}\Schedule #1 created by enrollment client
\Microsoft\Windows\EnterpriseMgmt{enrollmentGUID}\Schedule #2 created by enrollment client
https://learn.microsoft.com/en-us/mem/intune/configuration/device-profile-troubleshoot#policy-refresh-intervals
We have noticed users that use Windows Hello for Business log into the device faster than the AV/FW services are fully working after a restart and the login scheduled task (\Microsoft\Windows\EnterpriseMgmt{enrollmentGUID}\Login Schedule created by enrollment client) to kick off a sync reports a transient syncml500 error for those components to Intune on the policy and since the devices have never been compliant, they do not follow the error state grace period and get marked non-compliant. Additional manual sync may be required to get out of this state. Since the scheduled day 1 tasks don't run it is a manual process. Or you may have to wait until the every 8 hour sync happens. \Microsoft\Windows\EnterpriseMgmt{enrollmentGUID}\Schedule #3 created by enrollment client
https://learn.microsoft.com/en-us/mem/intune/protect/compliance-policy-create-windows#device-security
https://learn.microsoft.com/en-us/mem/intune/protect/compliance-policy-monitor#device-behavior-with-a-compliance-setting-in-error-state