The content descriptors selected in the age rating questionnaire — violence, mature themes, simulated gambling, and so on — need to accurately reflect the app's real content; under-declaring to get a lower, more appealing rating is a violation.
Commonly triggered when an app's actual content, such as user-generated posts or ad content, doesn't match the 4+ or 9+ rating it was submitted under.
"Your app's age rating does not accurately reflect the content available within the app, per guideline 2.3.6. Please update your age rating questionnaire."