I have no solid proof of this, but I've heard from at least two people who I would consider believable that their balance has been set to zero after depositing coins or logging in. They have not placed an order, nor are they able to, obviously with 0 BTC. Neither of them are vendors, and have lost a small-ish sum of funds. Perhaps they were phished or hacked, it just seems suspicious considering recent events.
This could just be a visual error and the coins will show up again in the future, but I figured it would be a good idea to give a word of caution to people. As a general rule of thumb, don't deposit any btc that you aren't willing to lose. I am personally going to wait a few days to see how things settle out.
Be safe!
if you still use nucleus after this past week or two, you screwed yourself like a dindopheliac in a pine forrest