Scam/“poorly optimized 4090” lies?

So, I just saw this computer for sale on my local Facebook marketplace. Just went up in the last day or so. It’s a pretty nice, high-end build. I’m not looking to buy it, but I was curious to give it a look given its specs.

The portion that I have circled in red caught my attention.

The seller is saying it crashes anytime a UE5 game is run due to poor optimization of the 4090. I’ve never heard of this before. Is that an outright lie or scam? Probably some hardware problem that isn’t being documented or the seller is trying to lie about? Or is that a legit thing?