1. In Salesforce Knowledge, go to the article list view.
2. Select several draft articles and click Check with Acrolinx to start a batch check.
→ The screen shows "Acrolinx check scheduled" but the following message also appears:
Lightning out App error in callback function
|Acroilnx for Salesforce Knowledge||3.4 and later|
Salesforce has reported this as a known issue in their product:
Lightning out App error in callback function' Message Below Flows Launched From List View Multi-Select Button
No workaround available. We need to wait for Salesforce to fix the issue.
It looks ugly but doesn't affect Acrolinx functionality.