A fraud, the “selected judge”, from the first round knows who the contestant is and of course the cooking style of that contestant…. (In the world of food networks, everyone knows everyone's cooking style.) Now the “selected judge” only has to play the dice in favor of the house…
If they want to be impartial, the judge must not know who the contestant is until the end, or else every time the contestant is revealed, that judge is no longer part of the jury and another judge must be selected.
Some decisions have been really disappointing, like the one they had with Chef Garces.
Bobby and the Titans are all very good chefs and overall the TV show is good, but to be fair the judge should never know who the contenders are and there should be 3 separate judges, one for each round.
Guest judges for obvious reasons tend to favor the house that invited them and will invite them again.