In
/oauth2-server-php/src/OAuth2/OpenID/Controller/AuthorizeController.php

in the validateAuthorizeRequest function is the call to
$nonce = $request->query('nonce');

If you are using POST to send your request to the OP, then the function will fail to grab the nonce for use in the Id Token. Needs to be changed to:
``$nonce = $request->request('nonce');`