Bayer have beaten Bayern twice in a row in 2019. After that, there were several draws and here they are winning again. But the most disappointing thing about this loss is that Borussia Dortmund have moved into first place in the standings and Bayern now need to play very carefully in their remaining matches to avoid losing points. Especially as they continue to play in the Champions League.
The Leverkusen team is quite a strong team. Bayern Munich should have performed very carefully in this match. But it cannot be said that Bayern Munich's overall performance in this match was very good. Bayern Munich's performance was somewhat poor. That's why Leverkusen got a chance to win the match. Perhaps Bayern Munich are more interested in Champions League so they don't give full effort in this match. Dortmund are now top of the table. However, the performance of the Dortmund team is not very regular. Consistency in performance is essential to stay at the top of the points table. I think Bayern Munich will be able to regain the top spot in the table in the next few matches.
I agree that Leverkusen is not a "bad" team but that doesn't change the fact that Bayern is the best team or at least should have been the best team. In a league situation where they lost the leadership due to this loss, you have to agree that they needed a win, doesn't matter who it was against, it could have been dortmund, leverkusen or schalke, doesn't matter who it is against but they needed a win.
Sometimes you lose even when the leadership is at stake, just last week Dortmund got a draw against Schalke, the worst team in the league. That is why this wasn't really a win from Leverkusen but more like a loss from Bayern instead because they could have won if they played like they normally play.