Well, my first guess would be not enough tension on the blade. Also, when you do a sharp turn, you need to give the blade a pause to catch up. Watch the blade when you turn you will see it does not turn a quickly as you make the turn. Pause a fraction of a second and you will see it the blade "come around" to the new direction, provided the tension is right. The thicker the wood the longer the pause required.
I have read posts where the tension mechanism on DeWalts can lose it ability do give adequate tension and I think there is an adjustment that can be make. Maybe some DeWalt owner on here will speak about that.