R54.16 seems to be doing something I can't prevent. Suppose you have memorized Amazon or Costco as a payee to aid in auto-complete, but you don't have a category because the things you buy vary from purchase to purchase. In earlier releases the generic transaction would just remain as the sole item.
Now every new transaction to the payee adds an item to the memorized list. This new behavior is incredibly annoying, and I don't see how the memorize payee settings can get me back to the old behavior while still memorizing a payee that is truly new.