I just implemented SSO (IDP and SP initiated) for a client who uses google apps as their IDP.
When I did so, I enabled MyDomain and set the redirect policy to redirect.
Users are now reporting that when they click old links from emails (eg. https://na5.salesforce.com/recordId) , they are not getting directed to the content. Instead, they are seeing a google apps saml error that states "No Saml Found".
My best guess is that Salesforce is checking for login before going to the url of the link clicked, but it never gets passed the authentication step.
I've never run into this in other implementations of SSO. Has anyone else seen this? I've gone ahead and updated all of their hardcoded urls in their emails to use a dynamic link, but I'd like to solve the redirect issue.