because when the SSO button is used in an OAuth App (3rd party integration) flow, the user must be redirected to the consent page / 3rd party callback page. (This is a little confusing because the OAuth app here is not the same as the OAuth provider/strategy for the SSO button)

In clerk.ts, the handleRedirectCallback method creates a RedirectUrls instance like this:
    const redirectUrls = new RedirectUrls(this.#options, params);

But the RedirectUrls constructor expects search params as the third argument:

constructor(options: ClerkOptions, props: RedirectOptions = {}, searchParams: any = {}, mode?: ComponentMode)
Since no searchParams is passed, the redirect_url from the URL query string is never read. The code falls through to the default '/'.
The Fix
The SSO callback page must:
Read redirect parameters from the URL using useSearchParams()
Pass them as props to <AuthenticateWithRedirectCallback>
The key change in the SSO callback page:
const searchParams = useSearchParams()const redirectUrl = searchParams.get('redirect_url') ?? undefinedconst signInFallbackRedirectUrl = searchParams.get('sign_in_fallback_redirect_url') ?? undefined// ... etcreturn (  <AuthenticateWithRedirectCallback    redirectUrl={redirectUrl}    signInFallbackRedirectUrl={signInFallbackRedirectUrl}    // ... etc  />)
This ensures the redirect parameters are passed to handleRedirectCallback via component props, where they get picked up by RedirectUrls through fromProps instead of the missing fromSearchParams.

particularly assuming clerk/javascript@cea6727