I just got this error on my largest backup set, even after the litany of issues I had with it last week that i’d thought i’d solved on my own. This happened to me on my very next automatically-scheduled backup (despite it having run successfully several times when kicked-off manually earlier that day).
Repair does nothing. I’m not interested in doing another Recreate now without evidence that it’ll actually work long-term. I’m about to just give up. 
Repair finishes almost instantly and claims this, even just moments after the above is seen when trying to run a backup:
