Wikimedia Bugzilla is closed!

1. Go to a wiki with FlaggedRevs (such as testwiki)
2. Log into an account without review permissions
3. Edit a FlaggedRevs-enabled page with no existing pending changes, in order
   to create a pending change
4. Log into an account with review permissions
5. Use the API (or ApiSandbox) to undo the edit you just made with the other
   account

The undo is successful, but it is not automatically accepted. 

When you carry out the undo operation using the standard index.php interface, the undo is automatically accepted.