User is performing too many actions

When attempting to create a media container, we occasionally encounter the error: "User is performing too many actions."
The Instagram account in question has created fewer than 400 media containers within 24 hours and has limited its Instagram posts to a maximum of 50 within the same time frame.
It seems unlikely that we have exceeded the rate limits, so what could be the cause of this error?
Client error: POST https://graph.facebook.com/v20.0/***/media resulted in a 400 Bad Request response: {"error":{"message":"User is performing too many actions","type":"OAuthException","is_transient":false,"code":9,"error_s (truncated...)