There are a few potential causes for Fortnite’s lagging performance on PlayStation 4. One is that the game is using a different version of the graphics library than what’s used by your console. This can cause some issues, as the game may not be able to render objects or characters as they should. Another possibility is that there are some files that are not being used correctly. If you’re seeing slowdown or errors when trying to play, it might be worth checking these files out and making sure they’re up to date.