With old forums and Microfocus (and I believe Novell) authentication I could login to bugzilla, then open forum in another tab and it would log me in without second authentication dialogue. On iPhone I could directly login to Microfocus (I just saved link to login portal) then open forums in the same page, press login and it would log me in using Microfocus credentials. No more with new authentication backend. I log into bugzilla, open forums in another tab and I still must go via the same authentication again. Nor does it work anymore on iPhone (and going via full site is less than pleasant on SE).It does not look like general issue, because other sites listed on IDP info page would recognize previous logon performed on another site. It looks like specific forum issue. I would not mention it if it never worked, but it did work before so it is regression to me.
You seem to be correct. But perhaps it is a work in progress. I logged into bugzilla yesterday. I had to separately login into the forums today, but I was still logged into bugzilla. This was with firefox. I also logged into the forums today, using konqueror. But, on a quick test, I am not logged into the bugzilla there.
Short term, there are no plans to change this, long term we are thinking about the possible solutions