So the issue here is:
- a user logs into your site
- you redirect them to discourse to log in there
- they end up logged in at discourse?
I don’t think this is a supported path. In general, a user would be on discourse, click login, visit your site for auth and be redirected back. If a user logs in directly on your site, they should stay on your site.
Typically how we do this is keep Discourse logged out, but when they click “Login” it’ll redirect back without having to fill out the authentication form again.