This is an odd one. Due to a new patch, PlayStation 4 and Xbox One versions of Grand Theft Auto V have seen their graphical fidelity reduced. This was picked up by fans, causing plenty of confusion on message boards.
Rockstar have noted the problem though and have said they are working on a fix. In a post, the developer stated:
We are aware of some graphical issues on the Xbox One and PS4 versions of GTAV after the most recent Title Update, and we are investigating a fix now.
This is a bizarre technical issue. It's weird that Rockstar messed around with GTA V so much it affected the games's performance, because by all accounts, it's been a pretty stable game. Hopefully it's resolved soon as this isn't good for anybody.