It is an interesting Q and all other things being equal and acknowledging the various points made, it is questionable that the Promise evaporates into thin air on the transfer of title from one member to another (howsoever the means and price), particularly when the wine is sat precisely where it was up to delivery to a domestic setting.
It feels fair that whatever would have been been done absent the transfer should still be done. Maybe it needs to be the original member who claims or whatever, which is something members can agree between themselves at the time perhaps.