I still have hashrate droops with the 0.33b6.
One has just occurs on my RX 570 4G after two hours of mining CN V8: from 1100 to 965 h/s.
It's the same hashrate droop I had with the b4 and b5 versions.
I fixed drops on CN-Heavy (and related) only. If i have good feedbacks about it, so i'll put it on V8 too.