I occasionally get a contact to add another forum user as a friend. This is nice, although I'm not sure what additional functionality they gain from an acceptance.
However, invariably when I get such a request, I can see in the notification menu drop-down that there is an message attached to the request (because the notification comes with the first few words of the message). But when I go to respond to the request the message is nowhere to be seen. It doesn't appear with the friend request and doesn't appear in my messages. There seems to be no way to read or respond to the message.
This has happened multiple times over several forum updates and never changes.