Yeah, I think that case is absolutely wild, because ostensibly the point of the recorded music was to showcase the strings.
Shows how much trust they have in their own product.
Now, unless the company in question got their new strings into Sona training data, I wager that the generated output has little casual connection with the product being advertised. If I found out IKEA's newest product looks nothing like on the commercial, because the ad was using generative AI and hallucinated something approximating the product, I'd be looking at it as fraudulent too.
Also, I think when judged by the court of public opinion, the overwhelming answer was "yes, it's fraudulent", or at least "misleading and useless" as most people even complained that the song sounds like an overproduced mess where any string would sound the same.