Two weeks ago, my production level suddenly dropped about 10%. I didn't accidentally sell buildings or anything, so I was confused.
Today I decided to level up the Wizard towers to level 9, and the production level dropped again.
I reloaded and saw that the production multiplier dropped about 10%. I tried to level up other buildings, and the multiplier also dropped by different values.
I thought that leveling up would increase production, not reduce it. I'm still confused! Is this a bug, or am I missing something?