How do you stop GPT's or chat to stop formatting/markdown its responses

How do you stop GPT’s or chat from formatting/markdown its responses?
I’ve tried positive; asking for plain text only. I’ve tried negative; no more markdown or any formatting. And it does, for a few responses, and then returns to the formatting(markdown) and lists. Can we have a setting to stop this?
Otherwise, it’s great, cool, and so on.