Oauth automatic account linking not working

Hi, what’s the secret to get ACCOUNT_LINKING = auto working for oauth2 clients?

We use LDAP auth on our gitea instance right now and we try to make OIDC mandatory, therefor we disabled Authentication source is Activated in the LDAP auth source and set ACCOUNT_LINKING = auto in the [oauth2_client] config, but users still end up on the Sign In to Authorize Linked Account dialog which is not working because the LDAP auth source is disabled