Friends list doesn't update all the time. Sometimes it works as intended, most of the time it doesn't. It wont show if they are currently playing a game, AFK, or even signed off. I have to sign out and sign back in to raptr to get the friends list to update.
It also very often doesn't update what I'm doing.
Very odd. We don't see this too often for me. Make sure there is nothing like a firewall/antivirus, but it's doubtful. Have you ever tried something like reinstalling Raptr? Or doing a config reset (I can tell you how to do one).
Additionally, if it keeps happening, you could try sending in your logs right after you notice something is wrong (like not updating)
To send to your log files:
1) Open the Raptr client
2) Right click on the Raptr icon in the system tray
3) Click on Help, then Feedback.
4) In the window that appears, check the box at the bottom (Send log file).
5) In the text box, please either describe the issue or paste the ticket number for your issue.
6) Hit send.
7) Post back here when you have sent your logs.
(Note: Make sure that you quit out of any game you are in before you send in your logs.)