Q: "Why did my ribbon go away?"

So my friend has been playing for some time now, and shortly after he hit lv 30, he ended up getting the yellow (friendly) ribbon. Recently it's just up and vanished, though he still gets friendly votes in occasional games, and I've heard it's not based on the total number you have, but if you keep getting honor consistently. (Which seems odd to me since I rarely get teamwork anymore, but I have 379 teamwork and still have my green ribbon.)

Anyone shed some light on this? He's pretty bummed. :(