According to a number of reports from various outlets online, certain titles are running worse on the PlayStation 4 Pro compared to the standard PlayStation 4 console. Most notably, Watch Dogs 2 has been singled out for underperforming on the hardware in comparison to what players would have expected.
While the game does maintain a 30 frames per second cap for the vast majority of gameplay and output a resolution of 1800p. Unfortunately, although this is significantly improved to the standard edition of the game, some performance issues do arise, including screen tearing and a drop in framerate.
The entire idea behind the PlayStation 4 Pro, and its upcoming Microsoft made counterpart the Xbox One Scorpio, is that it is a beefed up version of the original console that is able to max out the performance of games and other software so that they run better than originally planned.
The issue is likely just an issue of optimization, with developers likely to push out patches over the coming weeks to address these issues so that the PlayStation 4 Pro will not run any titles so poorly.