was playing in game #4710246. My opponent resigned just after I played Harbinger and was looking through my deck. I picked continue with Bots and the graveyard was not visible, so I had to pick don't topdeck to continue.
This is a general problem not only with Harbinger, but with any effect that brings this 'gallery of cards' interface to the screen. It is most prominent with undo. I just tested this on Hermit, Jack of all Trades and Annex and each time you undo to the point the selection has to be made, the 'gallery of cards' is not there.
I guess it has the same root cause, because all those effects do some kind of (re-)connection to the game (log).