Sorry to hear about your experience. Last minute gate changes suck, and that's a long walk from G92 all the way to the end of the F-concourse.

I make it a habit to always refresh my boarding pass on the United app up to the point after I clear security or leave the Club -- just in case the airline pulls a fast one on me.

And for the super-paranoid ones (like myself), I check the ship number assigned to my flight to see where it has parked/ will park on the inbound segment.