Steps to reproduce 

• Go to https://demoauthor.magnolia-cms.com/
• Add restorePreviousVersion to the action bar in dam assets app: edit /dam-app-jcr/decorations/dam-assets-app/apps/dam.subApps.yaml to add it as follows: 

  versions:
              items:
                - name: showVersions
                - name: restoreVersion
                - name: restorePreviousVersion
  

• Open assets app and go to /tours/shark_brian_warrick_0824.JPG or any asset
• Click on restore previous action in the action bar

Expected results

Due to none version, expect to see the full error msg in Notification app

Actual results

See 

Workaround

Remove comment and exception out of fields. See  

Development notes

Problem may come from info.magnolia.admincentral.apps.notifications.NotificationPropertySetFactory due to real Message has property exception, does not has comment. See    and both can't find in NotificationPropertySetFactory