According to an 8btc forum post today, a previous rumour turns out to be true that OKCoin have suspended transfer of bitcoin from its domestic site to international site, where bitcoin futures trade is hosted.
The OP said that:
(We are) informed today and the news had been circulated yesterday on a small scale.
The news was later confirmed by a screenshot citing chats with customer service of OKCoin.
“We are sorry. At present users are not allowed to withdraw BTC from domestic site to international site. But users are able to transfer BTC from international site to domestic site.”
http://news.8btc.com/okcoin-halted-btc-transfer-from-domestic-account-to-international-account
