Unsent message from New Chat appears after sending message in existing chats

Repro steps:

1. make a new chat

2. type in some text, but don’t send it

3. go to an existing chat from your history, and send a new message

The text you typed from step 2 appears in the input box after sending the message. This happens after every new message sent, not just once.

I’ve reproduced this on Chrome, Helium and Zen