The issue is that on Service Portal when a user accesses a knowledge article on "kb_article" page of Service Portal, there are following errors on the browser:
Script source code logged to console
Failing widget: 'KB Article Page' (c6545050ff223100ba13ffffffffffe8)
This error is caused by this line of code in the widget:
rec = rec.parent_id.getRefRecord();
This indicates that there is a bad reference in the parent ID. This is usually seen when there is a bad or empty value in "kb_category" field of the knowledge article in the Knowledge table [kb_knowledge].
To resolve the issue, make sure that the article has a valid value "kb_category" in the kb_category field.