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”.
They are doing this because a rotten corpse doesn’t force them to compete, they can do whatever they want. If MS didn’t shit the bed with the Series X/S, Sony would be trying harder to please customers, or at least not actively screwing them (see also: 800 EUR PS5 Pro without disc drive or vertical stand).