Actually… I have the same problem, but I think the messages are just not sent…
Also when I try to become a friend with somebody … after I click the button – the system redirects me to my own profile page without actually “asking for friendship” ….
I’m gonna read around if there’s somebody with the same bug.
it’s important to know that bug appeared a few days after I’ve installed the system.
May be the system’s in conflict with some of my plugins… or something.