It looks like I'm still experiencing some issues with the latest TestFlight build. But maybe this time the issue is a bit different: the intended page is being opened, but focus gets to the address bar, and the address bar is cleared, so it looks as if it did not open the page, but if I tap "Cancel" I can see the page.
This does not happen all the time though. So I'll try to figure out any pattern...
Update: I figured the pattern. If my focus was in the address bar before I switched from Orion to other app, then if I open external link in Orion, I can still see the address bar and the keyboard, not the page that I had just opened. Here is a quick screencast: