I can almost swear it's more leaky than before, but I don't know what triggers it, so it's hard to give context or more information.
I'm not talking about the leaks around reset which are well known and easy enough to avoid.
On 3 occasions I've seen it happen, many times in a row, not just one random message.
In every case, they appeared to be intended to be PMs. They always ended up one-sided, so it's not both sides of the conversation showing up.
At one point, perhaps the first time I saw this happen, I banned someone for 1 day, thinking it was deliberate and it went on for a good while, annoying the other users. Although the user didn't respond to any of my attempts to reach out and acknowledge it either. I think it was maybe deliberate but I'm not sure now.
The second and third times were acknowledged by the user. No bans needed, and in both cases it stopped, though I'm not sure what those users did. Maybe they reloaded the chat web page?
I'm sorry I don't have more information, or can provide any method through which this can be reproduced reliably.
4 days