Poor performance in codex recent update

[SARAVANAN200792]

1. split diff is not working
2. it was working fine to my prompts till last week.
3. it is forgetting if it is multiple point prompts before it was good.
4. not solving the exact problem and reasoning was so poor before it was too good.
5. Also it checks if the bug as multiple issues and it rectify it even if i didnt prompt it, but now its not rectifying it until i say it.
6. totally it is not working to my exact prompts.