Why can't I see my sent private message?

[selevo]

In one of the topics, I clicked the icon under the user’s avatar to send him a message. After sending, I saw a green notification that the message was successfully sent. But why don't I see it in the list of sent messages?
This is incorrect behavior of the forum engine.

I tried to Write a message to myself and after that I saw two messages at the top, the one I sent, and at the bottom, the one I immediately received.
why doesn't the same thing happen in the first option?

why doesn't the same thing happen in the first option?

[xrunner]

Do you have this checked in the message preferences?

Save a copy of each personal message in my sent items by default.