Insufficient error handling in QOAuth2AuthorizationCodeFlow::refreshAccessToken() and ::requestAccessToken()

The function QOAuth2AuthorizationCodeFlow::refreshAccessToken() does not appear to report refresh failures correctly, or if it does I have misunderstood the documentation drastically. When given an invalid refresh token, I simply get the following error message:

qt.networkauth.replyhandler: Error transferring https://<domain>/oauth/token - server replied: Forbidden

I would instead expect the signal QOAuth2AuthorizationCodeFlow::error to be emitted, but it is not. In fact from a quick glance over the codebase, it only appears to be emitted during the authorization code request, and at a quick glance there appears to be nothing externally visible for when there are failures during either requestAccessToken() or refreshAccessToken().

Is there another intended way to be informed of failures, or is this simply an oversight?

Thanks!