I think this may be a glitch in game review

So basically i was playing a 300 elo blitx game. i sacrificed the bishop so i could fork the king and rook. but 

when i sacrificed the bishop game review said its a blunder for some reason. im only 300 elo in blitz so pls tell me if this is a glitch.

Without a link to the game, it's hard to say the exact reason, but the engine evaluation of the position isn't a glitch. The evaluation is an objective look at the position.

What it doesn't take into account, which it really shouldn't, is the likelihood your opponent might take advantage of the blunder. However, it's still possible that your opponent could take advantage of it, so it's a blunder.

In fact, that was actually a blunder, because your a8 rook all this time was hanging to a bishop, so in fact you just gave away your bishop, to fork their king and rook (the rook wasn't even doing something useful in that moment, and your knight will be as useless as their rook was), and then exchange their bishop for your rook. In fact, you simply gave away your bishop

o

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