Hello Tom,
If you want to enable "autoposting" from a different Facebook account, you will need to submit the app for review. Otherwise you could really just ignore this message
For instance, if your "userA facebook account" created the app, and you used the same account to authenticate, it's perfectly fine. However, if you need "userB facebook account" to authenticate, you will need to submit the app for review with "publish_action" permissions.
This is a requirement that is set by Facebook unfortunately