Chelsea away when he got his feet mixed up and the ball lost under them
Last week at home to Burnley when he got skinned for the consolation goal
Villa away when he was too slow for Bailey
Almost one at home to Spurs when Brennan Johnson was too quick for him.
In all of them, there were other players to blame as well. He was never the only one. Last week Lewis lost the 1 vs 1 with the striker who tapped it in, almost one at Spurs never happened. On the other hand, last one against Spurs it was Walker who was too slow for Brennan Johnson as well, and he is the fastest RB in the world, and Ake made an error when he didn't even jump vs Kulusevski (responsible for a goal yesterday, but not a single person talking about it, Crystal Palace, too slow for Neto against Wolves and it cost us 3 points). Against Bailey, again, he lost a foot race with him, but other defenders were standing there watching and it was a deflected lucky goal. Again, Bailey, Johnson, or Neto are some of the fastest players in the league, and all of our defenders have lost races against them on occasion. It seems Gvardiol is not the only player who makes an occasional mistake or is too slow.
Anyway, against Chelsea, when he got his feet mixed up, Akanji completely missed the ball, and Walker didn't mark the goal scorer.
Overall, all of our defenders cost us goals this season, but it's about how many they prevent with their play or how much they contribute offensively. It's like saying let's sell Haaland because he didn't score a 1 on 1 yesterday. This is the equivalent of costing us a goal. It would be crazy, it happens, he will score the next one. The overall play is what matters.