Best thing to do is, if the price flips check the trade history; If there is a small trade that made the price flip it could be irrelevant. If there is a bigger volume while the price is flipping then it is real trading...
The price flipping often is a phenomenon of price gaps. These gaps get filled because traders are going to trade: i.e. they buy or sell. So when someone decides to buy or to sell their can either narrow that gap between buyers and sellers or increase that gap by placing a position at the marketplace.
Robots are also prevalent on poloniex that will increase that gap, or expose that a gap exists, and usually it's small orders therefore you can see the price changing alot, Yet no much action had happened... In other words it could look like 10% drop when really only $20.00 were spent on dumping 10%
Best recommendation in volatile times is to ease up on margin, go 1.5x not 2.5x; or in stages 1x, 1.25x, 1.5x and hold steady there. So incase whales come rippling over your position and you'll get lost in the fray.