Managed Delivery Policies are no longer running Detection Checks. New policies work fine. Error at SWDTaskBasedPolicy::BuildComplianceCheckTasks() - Altiris.NS.Exceptions.AeXSecurityException: The caller [Domain\username] does not have one or more of the specified permissions on the specified item 5cf58f60-2e31-4170-aab9-e053adfd6862
   at Altiris.NS.Security.ItemPermission.Demand(Guid entity, Guid permission)
   at Altiris.Resource.ResourceDataTable.DeferredLoad()
   at Altiris.Resource.ResourceDataTable.Load(Guid resourceGuid)
   at Altiris.InventoryRuleManagement.DataClasses.InventoryRule.GetResourceTable(Guid resourceGuid)
   at Altiris.Resource.ResourceDataTableCollection.get_Item(String strName)
   at Altiris.SoftwareManagement.Tasks.InventoryRuleCheck.ComputeRuleHash()
   at Altiris.SoftwareManagement.SoftwareDelivery.SWDTaskBasedPolicy.GetActualizedDetectionCheck(SoftwareDeliveryItem deliveryItem)
   at Altiris.SoftwareManagement.SoftwareDelivery.SWDTaskBasedPolicy.BuildComplianceCheckTasks(List`1 colDeliveryItems, Boolean bHidden, Boolean bIncludeConditionForSelf, Boolean bCalledForTargetedInventory, Boolean bContinueJob, Boolean runDetectionChecks)

Uncertain, at some point the security on each Managed Policies was corrupted so no user had rights to add the Detection check the client policy XML.

By disabling and enabling each policy, it resaved the security for all objects, including the detection checks. This resolves the issue.