Ref completely conditioned the game.
Even in the 5 mins or so build up to their first penalty where they were building momentum there were multiple fouls committed by Inter players that weren't given. If one of them gets given it completely breaks the flow. Then you have Skriniar, Di Marco and Brozovic allowed to fouls as many times as they like without being punished, again these change the games.
The first penalty in particular is ridiculous. Classic move by a well known diver, slow down and leave your leg hanging so that someone touches it and fall over. His leg hooks around Bonucci ffs and looks straight at the ref as he falls. A complete con because he knew he took abad touch, was at a bad angle and had 2 defenders near him.