I think this is 3rd or 4th Poloniex related problem I read this week. Bells are ringing for them.
I think it's time to leave Poloniex, we may see a new Cryptsy, Mintpal etc. issue.
The hackers almost always go for the biggest exchanges. When Cryptsy, and Mintpal were hacked they dominated the altcoin exchanges and their hackers mae themselves millionaires. Now Poloniex and btc38 are the top altcoin exchanges I get worried they could be successfully hacked like Cryptsy, and Mintpal.
I hope these problems are not because of history repeating itself, but I might move my coins out of those exchanges to be safe.