Missing "?" in Redirect URI

Hi,
while trying to integrate my oAuth API with GPTs, I am trying the oAuth Client. The oAuth Callback URL I get from gpt looks like

https://chat.openai.com/aip/g-<****>/oauth/callback

While prompting me to login to my website the redirect_uri I get is in the following format

https://chat.openai.com/aip/g-<***>/oauth/callback&scope=*&state=***

Notice that the querystring after callback starts without a question mark. This is prompting my server to say that this is an invalid redirect uri. This seems like a bug on gpt side.
Or am I missing something ?