Every time I've seen them recommended a target price far below what the current rate is for a stock recently, it's tanked, and then come back to higher than it

Every time I've seen them recommended a target price far below what the current rate is for a stock recently, it's tanked, and then come back to higher than it was before within a couple weeks. I have to wonder if they've been taking advantage of this (illegally) or if they've just got some incompetent people working for them that have no idea how much AMD is worth, for example. Seems like saying "that was just one of our analysts, others who disagreed still thought buying was good at the time" could be their cover for manipulating stock prices to their benefit.