Maybe what you encountered was a trading bot. There are traders who use a bot that will automatically execute trades for them and as I experienced it works like that - instantly placing and cancelling orders (this applies in other exchanges to).
Could be, but considering that Yobit has a delay throughout its entire platform, it might give people the impression that it's just a counter bot reaction, but I'm pretty certain that Yobit isn't shy of front running people's orders for its own benefit. I have seen the same be done through platforms as Cryptsy and Mintpal back in the days, and they are the prime example of a shitcoin exchange with shady operators.
Yobit is far worse than that, the only difference is that they are still operating, but I wouldn't want to test their durability even for one second. Playing Russian roulette isn't my style.