IDP 5 - NoSuchConversationException when clicking URL link from email and _saml_idp cookie set.

[Cantor, Scott]

> I have found a solution to the issue we were facing. The problem was
> that the original request to access a protected resource had come from
> an email link, which had caused the browser to set the Sec-Fetch-Site
> to cross-origin.

I guess it's possible this is an evolution of the original email link bug I mentioned, and perhaps they're not resetting the Sec-Fetch-Site header "soon enough" in the sequence of redirects and such to get things to work. Sort of a "private browsing context" by header policy rather than actually a separate process context.

That would seem to fit the symptoms. We have open issues around the whole "Office document links" problem and the behavior has never exactly made a lot of sense, but this might be the problem I suppose.

-- Scott