I'm trying to do regular checks of users for data consistency, including a check that they have their "manager"-attribute set properly

The "manager"-attribute gets set based on a different attribute that containes the ID of the manager. Not every user has this attribute set, but those that do, should have the manager-attribute set as well, and this is what I want to ensure with the policy I'm implementing.

This is what the query looks like for retrieving all users and the relevant attributes:

<token-query class-name="User" datastore="dest">
      <token-global-variable name="idv.dit.data.users"/>
      <token-text xml:space="preserve">basManagedBySeq</token-text>
      <token-text xml:space="preserve">manager</token-text>
However, before the query is completed and I can start looking over the data, I get an error-message about the manager-attribute:

DirXML Log Event -------------------
     Driver:   \Main\system\driverset1\Data Consistency Checker
     Channel:  Subscriber
     Status:   Warning
     Message:  Code(-8003) Unable to synchronize reference to \Main\data\users\H300019 from attribute manager.
Any recommendations as to how I can address this? Is there e.g. a way I can tweak the query so the DN gets returned as a string instead?