It was because of "operational requirements", i.e., your guess is as good as anyone else’s !
"A truly happy person is one who can enjoy the scenery on a detour."
My wife and I were on that ship and it limped into port with less than all engines functioning. We were supposed to arrive at 7AM but didnt arrive until 2:20PM. They probably are fixing the ship. As a side bar: I will never sail with Princess again and it has nothing to do with the ship.