VS Code extension keeps switching from ChatGPT Plus auth to API key / Codex mode

Problem

For the last 2-3 days, the VS Code Codex extension has started forgetting my ChatGPT Plus subscription state and switching me to API-key/Codex auth. It then repeatedly asks me to relogin before it will use the ChatGPT Plus subscription again.

What I expected

• Stay on my ChatGPT Plus subscription session
• Keep using subscription-backed auth unless I explicitly switch providers
• Not require constant relogin to get back to the subscription mode

What actually happens

• Extension silently flips to API key / Codex mode
• It forgets the ChatGPT Plus subscription state
• I have to relogin over and over to return to using the subscription

Environment

• VS Code Codex extension
• ChatGPT Plus subscription
• Started happening recently, around the last 2-3 days

Impact

This makes the extension unreliable because the auth state is not sticky and the extension does not preserve the subscription-backed session between launches or during normal use.

Notes

This is different from a simple 401 or one-off login failure. The issue is that the extension keeps reverting away from my ChatGPT Plus session and into API-key/Codex behavior without me asking for that.