[RC-Monster Mike]

I have seen this once before. The same thing happened. It also happened almost immediately (new motor). I also assumed it was a cracked magnet from the factory. The material is very brittle and a small hairline crack could easily go unnoticed. I suppose it could have been dropped at some point as well, landing on the shaft and causing the damage. Overall, I have had very few failures, but occasionally one must slip through the cracks (no pun intended!:)).