It looks like you're using an HTML note (not a markdown note).
HTML notes are not as well supported by Joplin as markdown notes. Try creating a new note (with the "new note" button) and pasting the markdown from this note into the new one.
It looks like you're using an HTML note (not a markdown note).
HTML notes are not as well supported by Joplin as markdown notes. Try creating a new note (with the "new note" button) and pasting the markdown from this note into the new one.