Cannot switch models — always reverts to Sonnet 5

Model switching does not work via /model command or settings.json. Any model selected (e.g. claude-sonnet-4-6, claude-fable-5) is ignored and the session always uses Sonnet 5.

Steps to reproduce

1. Start a sesion on sonnet 5. Once you start you cant leave.
2. Run /model claude-fable-5 (or any non-Sonnet-5 model)
3. Confirm with /model — shows the new model
4. Ask the model what it is — reports Sonnet 5

Also tried setting "model": "claude-sonnet-4-6" in ~/.claude/settings.json and restarting — still Sonnet 5.
Also tried using remote controll and selecting different models in the ui. UI shows its differnt but sonnet 5 still responds.

I cant even change to fable 5. I ahve usage credits for it but cant use them.

Environment

• Claude Code version: 2.1.220
• Install method: native binary
• OS: Linux