This error may occur when assigning provisioning roles either manually or through an automated function such as a PX Policy. It may occur for some or all of the user's endpoint accounts.
Assign user "[full name], ([UID])" provisioning role "[provisioning role name]": Failed to execute AccumulatedProvisioningRolesEvent. ERROR MESSAGE: Object '[account DN]' already existsEndpoint
This is a known issue that was fixed in IM 12.6.8 CR1 CP4. Please upgrade to the latest version of 12.6.8 if you're having this problem.