In the 38th minute of the Manchester City 3-0 Liverpool match, Van Dijk scored with a header, but VAR determined that Robertson was in an offside position and the goal was invalidated.
After the game, Liverpool coach Slott bluntly stated that this was a misjudgment, and Liverpool also contacted the Premier League Referees Company.
Referee chief Weber said on the show today: For situations where a player in an offside position interferes with an opponent, even if the player does not touch the ball, the referee needs to judge whether his behavior has had an impact on the opponent. This is one of the most subjective decisions we need to make. So it's no surprise that some thought the goal should have counted. I think it's important to look at what's actually happening.
We know that after the corner kick was taken, the ball was passed to Van Dijk. When the ball entered the penalty area, the Manchester City player moved outside, putting Robertson in an offside position. When Van Dijk heads the ball forward, we have to call Robertson for offside and judge his behavior in that position.
We know Robertson didn't touch the ball, but what did he do? When the ball flew towards him, he made an obvious ducking action three yards away from the goal. The ball flew over his head, and the referee needed to judge whether this obvious action had an impact on Donnarumma's save. This is where subjectivity comes into play.
Obviously, this is the conclusion they came to. They looked at that position and that movement, considering being so close to the goalkeeper, and ultimately made that decision.
Related reading:
Sloter talks about Van Dijk's goal being disallowed: This is a clear misjudgment. Stones' goal last season was valid
Protest that the goal was disallowed! TA: Liverpool contacted the referee company and believed that Van Dijk’s goal should be ruled valid