Keep in mind when you 1st open LW, all incomplete files you have will be queued. But as LW starts to settle, it will try to connect to each one, one by one on its own. QUEUED = LW is too busy to handle that file at that time. So "if" you have a lot of incomplete files, then after opening LW leave it to settle for 10-20+ mins before using. Adding more downlds to a long queue will only make them queue for longer.
Also, if you use the Resume/Find Sources function on too many files, this will queue your files for much, much, much longer. So use that function sparingly. Such as on 1 - 3 files at a time if you decide to use it. This function has side-fx as using up a lot of LW's & your computer's resources which is another reason to use it sparingly.