I have the same issue. Sent GNO to Poloniex over an hour ago, the transaction shows that it was successful but nothing credited to my account.

https://etherscan.io/tx/0x9b57c7f830e52dab6ba62d8e44c7578e5fc3336e792bdad8c1ae0f8c818b26c9

Opened a support ticket, hopefully they respond soon. I'll lose money if the prices fluctuates.