SSO Enforcement not redirecting to Group's Single Sign-On Page for some groups

Summary

For a very small amount of groups with SSO enforcement enabled on GitLab.com, potentially just a few, accessing the group in the browser without having logged in, doesn't redirect to the group's Single Sign-On URL. Only when using the GitLab Single Sign-On URL from the SAML settings (which includes the token), the redirect would work correctly. See https://gitlab.com/gitlab-com/sec-sub-department/section-sec-request-for-help/-/issues/179#note_1714584181 (internal issue) for identified rootcause

Workaround: While this hasn't been fixed, a workaround would be to access the GitLab single sign-on URL, which is shown in the Group's SAML settings, directly.

Steps to reproduce

Steps to reproduce this issue is unclear at this point as it only affects a few groups at this point.

What is the current bug behavior?

See above: for a very small amount of groups, possibly just a few, accessing the group that has SAML enforced, doesn't redirect to the Group's GitLab Single Sign-On URL.

What is the expected correct behavior?

If a group has SSO enforced on the web activity, accessing said group without an active session should redirect them to the Group's Single Sign-On URL. This should be the case for all groups with SSO enforced on the web activity.

Output of checks

This bug happens on GitLab.com