Did not replicate for me w/ Opus 4.6: https://imgur.com/a/4FckOCL
It did for me in Spanish: https://imgur.com/a/p3gOOnG
Perhaps different capabilities in different languages?
It's just not deterministic, even if you were to re-run the exact same prompt. Let alone with the system generated context that involves all the "memories" of your previous discussions.
It fails in chatGPT in french too:
https://chatgpt.com/share/6992dc05-003c-8004-9f7f-c40c7fac64...
Interestingly, just typing "Think" as a response makes it get to the right conclusion: