FYI: They blame you 
Hi Pod,
Thank you for taking the time to reach out to us!
We understand your concern about the HTML format when copying and pasting from Discord.
We’ve reviewed your issue, and it appears that different applications handle copied multi-lined text differently. Some maintain the original line spacing (like Notepad or Google Spreadsheet), while others don’t (like Google Docs or Discourse, as you’ve noted).
We aim to ensure that our functionalities work across multiple platforms and applications. However, because every platform and app manages these functions differently, it can be challenging.
I hope that sums things up! But do let me know if you need something else!
Cheers,
Nico
It doesn’t look like Discord or Discourse will change, so I guess I’ll just have to remember to do CTRL+SHIFT+P to so a magic paste if I ever copy from Discord again, and this bug can be here incase anyone else comes across the issue.
(I’ve tried saving their CF_HTML contents to a file and looking at it, and it has the line breaks in Firefox, Chrome, Edge. I don’t know enough about web dev to know if what they’re emitting is “valid” html, or simply HTML that a browser will begrudgingly render correctly because it’s interpreting it as HTML 1.1 or something)