The prince's secret bug - Petrus is not at location

Hello,

i am trying to complete above mentioned quest, but when i am at the step for questioning Petrus and looking at the map.
He is just out of bounds and nowhere near his location in the castle of the governor.
This is basically preventing me to complete the game, is there anyway to fix this?

Thank you in advance.

forgot to add on PS4 but most likely can happen on all platforms