Still an issue with outlook webmail when logged in on the latest Orion Version 0.99.121.1-beta (WebKit 614.1.20).
I am wondering if this has something to do with redirects? At least the outlook webmail does a lot of redirects before actually opening the webmail.
Furthermore, it seems that its mostly an issue when the Outlook webmail session is expired and has to be reestalbished.
Not sure if any of the above will give more insight - but that is at least my findings/ideas.