yobit puts some fake trades in history so they can foul some guys to trade, lol so desperate.
Proof? Oh, you have none. No need to be so butthurt that you coin is going down in value by the minute.

Go to yobit BTC-WAVE, click on 7 day chart. See the grey columns? That means 50+ BTC "bought" at that point in time. Now look at the order book and riddle me this: how can you buy or sell 50+ BTC worth of WAVE in one go, without significantly moving the price up or down? That's proof enough for me. Same can be observed at LSK and ETH at yobit, by the way.
I have the suspicion, that the price dump at yobit is either initiated by yobit itself to revitalize actual trading, or by someone who wants to buy Waves elsewhere (probably here in the market section).
The price dumped happened because they tweeted they would manually be accepting WAVE deposits... First people to deposit dumped, not that hard to conceptualize. I don't think any foul play is going on, higher volumes earlier with little price movement were simply a sign of a lot of action on either side. IOf course the first people to sell instantaneously will take that option, that's only natural.