[Bug] Claude generates non-English words unexpectedly in English conversations

Bug Description
Earlier in the conversation Fabel spit out честный (honest) in russian in the middle of a english sentence. The word is correct, but why russia?

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.174
• Feedback ID: 5ce98512-9bb8-4ca3-b115-68945e269ffa

Errors

[{"error":"Error: 404 {\"type\":\"error\",\"error\":{\"type\":\"not_found_error\",\"message\":\"Claude Fable 5 is not available. Please use Opus 4.8. Learn more: https://www.anthropic.com/news/fable-mythos-access\"},\"request_id\":\"req_011CbztF9xYa3nNH1Br4RcRN\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:12:66250)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:52:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-13T07:43:27.015Z"},{"error":"Error: 404 {\"type\":\"error\",\"error\":{\"type\":\"not_found_error\",\"message\":\"Claude Fable 5 is not available. Please use Opus 4.8. Learn more: https://www.anthropic.com/news/fable-mythos-access\"},\"request_id\":\"req_011CbztTcPMn6jKhuY5nsroS\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:12:66250)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:52:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-13T07:46:16.126Z"}]