It's hard to say exactly how much credit Astra gets if its training contained the research notes of Levent Alpöge and Tristan Buckmaster. Surely it's impressive to generate the result even if working from their notes but it muddies the waters on its capabilities quite a bit.
From https://openai.com/index/navier-stokes-solution/:
> we cannot rule out that de-identified data derived from their usage of our products helped improve our models