Fable 5 suddenly went offline, and the main reason turned out to be that

the United States questioned that the relationship between SK Group, which owns Hynix, and China is too close.
SK Group has SK Telecom, a major Korean telecom company, and one of the few companies that gained early access to Mythos.
But the U.S. government found that SK Telecom had previously cooperated with China Unicom, and SK Group's subsidiaries also have extensive businesses in China, including energy and semiconductors.
They are very concerned about whether SK has some kind of connection with China.
Subsequently, Amazon researchers pointed out to the White House that Fable 5 has a bypass security issue, causing the U.S. government to doubt whether Anthropic can control its most powerful AI technology.
Finally, the White House demanded that Anthropic only allow U.S. citizens to use Mythos and Fable 5.
Anthropic found it too difficult to enforce, so they simply took both models offline.