My issue comment drafts are always persisted locally and not lost on refresh. Not sure why you're seeing otherwise. It is supposed to work that way. If you're seeing otherwise, please consider opening an issue.
Same here. I often force-reload issues/merge-requests because I see a popup "Press Ctrl-Enter to submit" which won't disappear, and obscures the content I'm trying to write/preview.
I've been pleased the text-content persists.