It shows the Cup trophy you got when you were level X. Your team has a level (Teamlevel) which matches the League you have been promoted to. When you check the trophies or position you ended up in a specific season, it will show you how you did on that season in each competition. So, in season 14, you reached final in Cup and lost, so trophie with a 2 for you in season 14 in Cup.

That doesn't mean Cup is level 14. You got the Cup trophy while you were level 14 (as a team)