Two individual chats with the same person

So, a few months ago I tried to get a friend using Keybase. I sent him a chat message through Keybase using his Twitter handle. He never got around to signing up for an account, so that chat has remained in my chat list with only my one sent message.

Recently, he did sign up for Keybase. He sent me a chat request somehow, and we've been chatting every since. However, this chat is separate from the one we had started, so now we both have two instances of our two-way chat in our message lists. (We both see both chats.) See the screenshot. The one at the top is the new one he sent that we've been using. The one at the bottom is the one I sent sometime ago. Notice: the usernames and even his profile picture are the same, so Keybase is aware that this is the same person/account.

I don't see a way to delete the old, duplicate conversation. I can block it, but I fear that would block both of our chats. Is there a way to clean this up? Did a bug cause this?

Keybase GUI Version: 1.0.22-20170502110012+a3c4856

No source files or tests are named. Start by reproducing the pre-signup and post-signup chat flows in the Keybase GUI, then inspect how the chat list identifies conversations. Done means the two chats with the same person are consolidated or the old duplicate can be removed without blocking the active conversation.