If the issue comments are to be believed it could be related to the codex system prompt itself so likely just the harness. I agree the wording is weird but they

If the issue comments are to be believed it could be related to the codex system prompt itself so likely just the harness. I agree the wording is weird but they appear to be referencing GPT 5.5 in Codex because yeah there isn’t a GPT5.5 Codex model.