staticwebapp.config openIdIssuer from environment variable not working

**Describe the bug**

We're using a static web app with Azure AD auth (our own tenant) and the current set up looks like this:

` "auth": {

"registration": {
"openIdIssuer": "https://login.microsoftonline.com/xxxx-xxxxx-xxxx-xxx/v2.0",
"clientIdSettingName": "AAD_CLIENT_ID",
"clientSecretSettingName": "AAD_CLIENT_SECRET"

}
},`

Obviously the client id and secret are pulled from the config in the azure portal. My issue is we have test and production versions with different tenant/provider ids in the openIdIssuer string. When I try making this a config app setting e.g (AAD_ISSUER) my auth breaks.

Is there a reason this can't be an environment/app setting variable or am I doing something wrong?
Also is there a way to list the values of these variables?

Thanks

**To Reproduce**

Set the openIdIssuer URL in auth config to an environment variable/app setting