A couple of maybe's. The new Mk XXII has an Anschutz action with a one piece circular collar/spring with integral extractor hooks on each side. The left one may be holding a little too hard and causing the right side extractor to release first. The other thing that comes to mind is if your scope has target knobs and/or is mounted very low, The ejected hull may be hitting the windage knob or knob cover.
I would take the scope off and check ejection. If it ejects cleanly, watch the trajectory of the ejected cases to see if you can determine what they might be hitting. You might be able to shift the scope forward or backward enough to stop the hull from hitting a knob. If it pops straight up and/or falls back into the rifle, call Weatherby before you do anything else.
Good luck, Tom