1. In an attempt to make the ball go straight, or probably even more likely...NOT GO TO THE RIGHT.
2. Because of a poor grip. A very weak grip may cause this.
3. Pivot problems... various Zone 1 problems may cause the club to get off plane, then the player has to try to steer the clubface back to the ball to save the shot.
4. Poor concept.
All these things are most likely done unknowingly by the player, except possibly #4.