I have noticed this twice: my team performs strangely (poor performance - losses, draws, and unconvincing wins against much lower quality teams) when there is a construction going on. These constructions are those related to the stadium, for instance, stadium upgrade or grass upgrade. In the next match after the construction is over, my team performs as it should.

What kind of thing is this? I'm so disappointed and annoyed given that I have already invested a lot of money in that game by buying tokens to build the team and so on. If this continues, I will quit the game at the end of this season, given that I can't upgrade certain areas without any performance penalty .