Hi Iv been mining a few years now and from my experience that mining direct to exchange is more likely that your mined funds will be lost with out trace.
Best to download a wallet for your mined funds to go to so you can track and trace any problems with payment processing.

These address maybe used by the attackers hitting the pool and blockchain getting rich fast from other miners effects.

Most of my experience also with what i know about nicehash and cloude mining the mine on one site and send rejections to another side know as orphans and when someone finds a block the attacker that's spaming the orphan or rejected shares they get the funds.
I may not be 100% correct but that's my experience and interpretation.