A few posts above there was a discussion about whether Robert Lewandowski departure had an impact. Of course, every departure has an impact for a team. That is also the case at work. When someone leaves the job we do not find a 1:1 replacement. But I do not think that is the question or the problem here. The problem is in the defence. They lost because goals were scored against them. So the focus from Bayern should be the defence.
I agree that Lewandowski's departure has had an impact (whether it's bad or not). But I don't agree that they only have defensive problems, because when their defense is good but they can't score it means they won't win the game. I said they played well, it was just that they had problems with finishing, that's what I saw. If they had a good finish, when they conceded one goal and created two, it would have been a win for them.
I understand that you may imagine defense could be part of it and we can't say Lewandowski as "only" reason, but we can say it is the biggest reason. That team never had to rely on anyone else for scoring, it has been so many years since Lewa played for them and they had a tactic in place, working amazingly for them. That is why we could consider him the biggest reason, and defense having a bit of a role in there too, but a smaller one.