Hi again Peter,
That is very interesting and I see your confusion here. I repeated the same test and was given the same results without your brand name in query.. Still when Google is listing the title they are listing your brand name.
It seems to me that they really want your brand name to show in this title. Why? I'm not entirely sure. But that's what they're adding to your title here..
Try shortening your title on that page by a word or two and adding a pipe (|) and "Mobify." Make that your test page for this issue and see what Google does with it when the change populates. I have a funny feeling it might pull your full title at that point.
Most sites out there try to drag their domain/brand into each page title anyway. You can call it "best practice" or just a "funny habit" but I feel like this is what Google is looking for with your site.
I'm incredibly curious, so if you don't mind trying this out and reporting back I would be greatly appreciative.
Thanks and good luck!