Assuming that all the things you are posting here are true, this is not a good sign for Poloniex and I think there is really a big problem on their side that must be addressed as soon as possible. I would not wonder if soon they would experience migration of their clients to other exchange. Poloniex has already a good following and in fact many of my friends are using Poloniex. All of these are happening at the same time that the site is kept on fighting many attacks.
I have read the same problems over and over about Poloniex. I have not used them because I do not trade with altcoins but that is a sign that the exchange might have scaling problems of its own. They have broken the record in terms of volume and the more traders use them the more the bugs and glitches appear. It would be a good decision to stay away from them and trade somewhere else.
The same was said of MtGox years ago. There was also Roger Ver who vouched for the exchange and said that it was solvent. A few months later it was it was exposed as illiquid and cannot pay back their customers. I am not saying that Poloniex is insolvent but you should not always believe what they tell you. Keep your Bitcoins in a wallet you control.
a lot of the major sites are turned to the shady site.
