"With patch version 1.04 installed, the PS4 version's constant 1080p output comes at a price. We catch dips between the 50-60fps lines during battles through Seoul's streets - with drops to the high 40s caught when throwing the 'threat' grenades to scan the area for enemies. Even in perfectly matched scenes, the Xbox One's performance tends to hold at a perfect 60fps by comparison."
I knew there was something going on with the PS4 and this game.
to be fair, I did not notice too many issues with smoothness or frame rate during MP, it was mostly the campaign