Thanks for the report! I'll keep an eye on it. So far we aren't seeing any other reported issues, so it's possible that a browser extension, or something else in your setup is messing with the SSO flow.
Redirect back to localhost:3128 is normal, that's where Kiro is watching for a callback, but the missing state is not normal. Something may have stripped the info out of the callback before it occurred, which is why I suspect an extension in your browser.
Will keep an eye on this though!