There is an error in socket.js which cause unexpected behaviour when a socket is in multiple rooms and leaves one of them. In some cases socket.rooms doesn't reflect the rooms the socket is actually in anymore.

the line:

self.rooms.splice(self.rooms.indexOf(room, 1));

should be:

self.rooms.splice(self.rooms.indexOf(room), 1);

Also when using socket.leaveAll, socket.rooms doesn't get cleared. self.rooms = []; should be added there.