When I saw the newly removed items I wondered about it also since some of them I had already dibbed. They are still in my list of "bought" items though. I assume that the entry was removed because the lister definitely doesn't have any additional packs to add and wants to remove it from their own list...not that they didn't have any to fulfill existing dibs.
I leave entries on my main swap list if it is something I plan to swap again in future swaps/years. That way all I have to update is the quantity and the date collected and then re-enable it (green check) for a future swap.
If someone was totally out of something and didn't plan to have it in the future then I could see why they might remove it from their list, unless there was something in the notes for it that they needed to fulfill dibs since the notes don't show up on the "bought" or "sold" list.
When packing up some things I did increase the quantities on the things below that got down to zero.
Carolina Allspice (Calycanthus floridus)
Nodding Onion (Allium cernuum)
Prairie Onion (Allium stellatum)
Spurred Butterfly Pea (Centrosema virginianum)
