Apologies for the wait, @j.jaffeux. Likewise, I apologize for the pasted content being utterly broken in its formatting - it appears that I forgot to adhere to my own advice, so Discourse broke it. I’ve remediated it now.
Basically, pasting a significant amount of Markdown can consistently cause Discourse to reformat it when it’s pasted. The problematic part of its reformatting is that it adds line breaks to the pasted content.]
However, if the user prepends ``` before they paste the Markdown, it is not reformatted on paste. I’ll attach a video as an example.