Why and how. When the starter starts the motor and you let off the button, power is cut to the starter line by your remote solenoid.
However your starter still is spinning, and still has coiled pole pieces surrounding a rotating magnet. i.e. it has all the makings of a generator. A terrible ineffiecent generator, but it will still creat some electricity.
It actually creates enough to keep the solenoid energized for a fraction of a second. This causes the drive to stay engaged for a fraction of a second longer. Which then cause the starter to spin faster (lots of starters are in the 16 to 1 gear ratio with the flywheel) So if start, and typically crack the throttle slightly, and hit say 1500rpm before the starter disengages, it sees 24,000rpm. The drive clutches either slip, or the bushings/bearings see lots of extra wear.
How to change it back. There are a couple of threads about it, with drawings I think, i will see if I can find them.