Same thing here! I have been mining to a kraken bitcoin wallet using nicehash for 2 months now. Finally, I am at the edge of getting the deposit from nicehash, I logon to kraken and my bitcoin deposit wallet disappeared! WTF! The deposit list it just empty, while I am 100% sure I got my XBT wallet address from kraken.com, when I create a new wallet, it is a different address. So all this money and electricity is wasted. Scammers.
Could this have anything to do with this mail of 26th October from Kraken
Before making your next bitcoin (XBT) or tether (USDT) deposit you must create new deposit addresses. Please do this as soon as possible - as of October 30 deposits sent to old XBT or USDT addresses will be delayed and may be charged an extra service fee.
OK So they expect all miners to change their payout wallet address and you only get 4 days to do that? What about pools that have a minimum payout treshhold? You can't change your wallet in a pool and transfer your pending balance to another wallet! So they just throw away the wallet 4 days after the email?? What a scam! I needed to mine 2 months to get at the minimum payout treshhold of 0,01 XBT, only to find kraken has deleted my wallet!
So they email you saying that keeping the old wallet will cause "delays", but in reality they just delete the wallet.