I've noticed this since launch but it wasn't as common. Lately it's always wrong. Iv'e noticed it affects invites as well. Example: I'm waiting in lobby, not matchmaking lobby but just regular pre-game lobby. I send an invite. Friend accepts invite but is told invite is no longer valid or something to that extent. Friend pulls up friends list through game and it say I'm in a match or not online. Very frustrating. I love sending invites and waiting like chump only to check the main friends list from the dash and see they are not online.
While we're on topic why can't I just send an invite instead of it having to load and ask for some pointless message? It was so much faster in the old COD's on 360. I know it's a Sony thing but still a PITA non the less.