as others have said, incidents of locked fan (and their associated aft stages) have occurred. Usually due to the blades windmilling backwards on the ground in a stiff breeze in combination with tight clearances. There is a complicated reason why it is more likely to be due to backwards motion.
This can easily go unnoticed during walk-around and then during the start sequence there is no N1 for a period of time. Somewhere after the engine lights off and begins to spool up the high rotor the stuck fan blades overcome this friction simply due to the torque from pressure drop across the driving turbine rotor.