What blunder? The ref got it right and var reviewed it and clearly showed there was zero contact on the ball from the fcsb player. The first 3 angles actually look like a reffing howler but the 4th angle clearly shows zero contact made to the ball so 100% a foul. Not that it made a difference anyway
Video title is misleading. Ref said he should have let the move continue instead of blowing the whistle. The decision was correct - Clearly a foul - Not a Butland blunder.