I don't think Anthropic have said anything of the sort.
Microsoft published it as 6.1*10^27 FLOPs[1]
Elon has claimed the are also training a 10T model because "Some catching up to do"[2]
[1] https://x.com/scaling01/status/2061897540161728791
[2] https://x.com/elonmusk/status/2041754402239975479