"Group" of 2 DM oversight

If you're in a direct message with a friend, and a 3rd person is added, that feed becomes a "group". If the 3rd leaves that group, the app doesn't downgrade the DM, instead it leaves it as a group saying "2 members". You have to leave the group, then send your friend a DM to reset/delete it. It would be nice if it auto down-graded it to a DM.