The activity system works differently for everyone, some peoples activities which I've seen, updates along side their post counts while some works randomly. You have to be patient mate.
You need to wait so do I
Yea I also noticed yours @ Nwada001 it's been long since yours decided to slow down. just a little more patience and it will add up. For both you and miachloe, I guess it's a sign of good quality posters as you already have merits enough of another rank.