I'v mined to exchanges for more then 5 years now with not to many issue just don't send small amounts of coins if there wallets down you get your coins when there wallet comes back on line .I also bought Signatum on there exchange 300,000 and it's also missing long with the 195,000 I mined they where hacked two weeks ago when they forced the 2FA on log in's
Good reasons not to mine to an exchange:
1) Exchanges do not support generated transactions from pools like Eligius, P2Pool
2) Exchanges like Yobit change your wallet addresses sometimes - meaning you will not be credited your coins - you will loose them.
https://bitcoinhwwallet.com/2017/08/08/yobit-net-users-caution/ 3) Blockchain forks and wallet updates may cause you to loose your coins.
4) With most exchanges it is against their terms and conditions.
5) Exchanges REALLY DON'T LIKE IT and WARN against it.
6) It causes unnecessary strain on an exchange wallet and can contribute towards wallet problems.
