I sent a seller a question about something he's selling. Within less than a minute, I found the answer online and changed the message to "I'll take it". He responded about 20 minutes later and the question was still there. I asked him if the question was still there and he said it changed after he responded. I wish I could be more concrete with what changed when, but that's what happened. It seems the edit isn't immediately appearing on the other side of the conversation even though the it showed on my end right away. It was weird.