Steps to Reproduce: Take an existing text, and insert a new paragraph at the end of a word but before the next space. The space is then carried over to be the first character of the next paragraph. It gets nowikied in order no to create a preformatted line.
Suggestion: Remove spaces at the beginning of paragraphs, as they'll get nowiki'ed. If there are cases where we actually want that, then instead of removing them on save, we could remove them during the creation of the paragraph, and only keep them if they're added manually by the user after the creation of the paragraph.