Doh!
I just realized I was running 12.4 version.
Updated to 12.5, so far so good.
@Valgar nicehash released new version of the miner with updated CM miners, check if it helps.
12.5 has the issue as well.
The problem is almost certainly on nicehash's side. Come report your problems here, doubt nicehash monitors this thread:
https://bitcointalk.org/index.php?topic=562238.msg19402626#msg19402626