Random switches to GPT model

[itvgf]

There is #279972 but has been closed for no reason.

• Copilot Chat Extension Version: Don't know where to find this since the Chat extension has been integrated

Version: 1.124.2 (system setup)
Commit: 6928394
Datum: 2026-06-12T00:12:36Z
Electron: 42.2.0
ElectronBuildId: 14159160
Chromium: 148.0.7778.97
Node.js: 24.15.0
V8: 14.8.178.14-electron.0
Windows_NT x64 10.0.19045

• Feature (e.g. agent/edit/ask mode): Agent
• Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): OpenRouter, several models

Steps to Reproduce:

1. Copilot Agent Budget is empty/100%
2. Use a model via OpenRouter
3. VSCode/Chat randomly resets to GPT 5.5 Copilot

This is "reproduceable" and happens on different systems