Wow, this is awful. Some people reported that these ads are also very petty and not necessarily related to the game, like apparently Elden Ring shows an ad for a licensed mousepad when you hover over the game now…
Edit: Playstation Product Manager says this is actually a new bug. I really doubt it but they do seem to be “fixing it”.
I think it is intended behaviour, but it’s not meant to be a system wide thing. I can see this being useful for multiplayer and live service games.