should I be worried?

this actually ties into my thread yesterday about high revs.
My wife was doing some yard work with the grizz today and it was acting up again and said there was quite a bit of grinding going from park to reverse. I am not home so I am guessing it was reving far too high to shift.
She says its shifting thru all gears fine now but my question is should I be concerned about major damage or being it only happened once and she says its shifting fine since it should not be too big a deal?