Overstable discs are likely to hyzer out. That means they are likely to fall away from the direction of the spin. For clockwise spinning throws, the overstable disc wants to fall to the left. This is also called fade. Disc dog plastic, with the exception of Z Discs by Hyperflite are understable.
As discs get beat up they exhibit more understable flight tendencies. A headwind also makes a disc less stable and a tailwind makes it more stable.