I beg to differ.
For example, I 'bought' an item the other day, but the seller realised that I had only re-bought it because I never received the first one I bought from him, and he decided to send me a replacement without further charge.
The item that I re-bought and the seller cancelled is now listed as 'Cancelled' in my purchases list.
But if I then leave feedback on any other random item I have received, I am presented with this list of Items 'requiring feedback'. And the cancelled item that I never received still appears in that list.