Upgraded the latest version of SAML & it worked for me.
Did you have a look at the possible solutions Robert has mentioned here. Specifically his second comment about the originURL.
Do does your index.html automatically redirect the user to the SAML login page? If so, you need to create a copy of the original index.html, e.g. index3.html and configure this page in the SSOLandingPage constant to avoid the redirect loop.
Another issue with an endless loop can occur if your app and your IdP don't share the same domain due to "Strict" SameSite cookies. In this case, the app and the IdP either need to share the same subdomain or the value for SameSite cookies needs to be set to "Lax" or "None".