This doesn't completely match what GN reported or what GN said Billet told them.

In the video, they actually mentioned that Billet's device was intended for a 3090, but "they (Billet Labs) think it should work with a 4090 too."

According GN Billet said that they told ltt that it might work for the other card but that it wasn't tested.

Additionally, the device was sent to LMG without an expectation of return. They asked for it back after the poor review, but when it was originally sent over, there were no strings attached.

This I haven't heard before but I do find that highly unlikely. Most companies aren't willing to permanently part with a prototype considering how expensive they tend to be, trade secrets and the low number they have. Billet labs are apparently a two person start up making it even more unlikely.

and it was likely mismanagement rather than malice that caused them to sell it.

I don't think personally that it was a question of malice as such but most of the criticism from GN was based on LTT being mismanaged where speed was more important than being correct. So still not a good look for them.

I also think that GN probably should have asked for comment before releasing this kind of criticism against arguably their largest competitor.

GN responded to this in a follow-up. I think they said something along the lines that they don't do it for other companies either. I'm personally a bit divided. Most of the information presented was factual and not of the nature "he said she said" with the exception of the Billet question. The size difference (especially when in similar scenes) could also be seen as a reason not to reach out so that the story isn't buried by the larger companies reach and resources.

Important considerations, especially considering Linus first response where I felt he played around with semantics a lot. What I like about GN is that they always seem to back things up with references.