The Hoverboard shakes!

My cousin and aunt tried riding it this past weekend. While my cousin had been riding it for about 30 minutes, she said it started shaking.

"Get off! Get off!" I exclaimed. The last time I felt a board shake, it was due to me meeting the top speed. In this case, the hoverboard was only going around in circles at minimum speed.
She flew off as we watched the hoverboard from a distance.
My dad comes closer and starts reaching for it.
From what I've read about these things, I knew enough to warn him, "No, no no. Stand back!"

I watched it. Kept watching.
Nothing.
No fire.

I felt the bottom of the shell and it felt cold. No heat whatsoever. Watched it for a bit longer, left the garage where it was being stored on the concrete floor with no combustibles nearby, and kept revisiting it every 15 minutes to be sure the garage was still there.

No issues.
Was a bit worried about storing it in the cold garage, but we ended up doing it anyway. It was inside the bag which probably didn't do much for warmth but the hoverboard worked just fine the next day.

I also learned that there's an automatic shutoff (not the charging), but on the board itself. I had left it on while walking around uneven surfaces where the hoverboard wouldn't be able to go. 10 minutes later, I returned and the board had turned off. Saves battery. Good thing.