You don't have to agree with the facts. Doesn't make them any less factual.
Sorry.
Maybe you weren't clear enough in your original post. Are you ONLY shuffling, tweaking, unshuffling and then reshuffling without ever returning to the playlist menu? ie. You're not reshuffling by selecting the same playlist, are you?
If the first is your case, then I can see merit for your suggestion. Because you can treat the list in memory as a "master" list - and the operations you perform to it should be preserved until you REPLACE the list.
This isn't what I understood from first reading your message. If that's the case, I don't know if it's a bug, just a different approach to implementing the current feature set. It would make for a useful suggestion for a future revision though.
Bruno