[BUG] Opus used even though Sonnet Selected

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

I dont have Opus enabled anywhere in my settings and yet im seeing opus use shoot up even though I'm set to using sonnet no matter what instance of claude code im running

<img width="859" height="105" alt="Image" src="https://github.com/user-attachments/assets/a4382435-8dc0-419a-81ae-4412b235ac8e" />
<img width="646" height="115" alt="Image" src="https://github.com/user-attachments/assets/e41a9300-705e-42b4-909a-737967bc6d4c" />

What Should Happen?

Opus use should be at 0 because it should not be routed to. The most I did was turn thinking on for a bit. But that nor anything else should be triggering opus under the hood because it was not set. Opus causes usage to skyroket despite never being selected

Error Messages/Logs

Steps to Reproduce

Impossible to reproduce as its unknown to the user when it is happening. This is an internal error

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.50

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

This causes rates to usage to skyrocket despite never being enabled. Must be fixed asap