I think there's a bug in Disguised Event and AFK points.
Just as you said, it went back to the way it was, disguising random mobs and indicating the name after each round.
But last night, the NPC was just disguising MVPs, I thought it was due to the sudden disconnection of the server. And yet, after joining today's event, it was still only disguising MVPs.
Regarding AFK points, since yesterday, I don't receive any Gold Coin from being online. Same for the reason I stated. But, now I've been playing for hours, and still nothing.