We were getting the same issue. The only "fix" we could find is manually clearing the local storage and navigating to https://{authDomain}/{tenant}/b2c_1a_signup_signin/oauth2/v2.0/logout?post_logout_redirect_uri={redirectUrl}
instead of using the library's logout
method.
Just doing the one or the other (clearing local storage or navigating to the logout url) doesn't work in FF, although it does in Chrome.
We tried this, cause I noticed that in Chrome the logout url gets called, but it doesn't happen in FF.
Hope this helps.