I had the very same problem. Only I caught it before it happened. I bet if you look on the sidewall of those tires you will find a D. O. T. tag. Which means that tire was a retread. I used to recap tires for Bandag, it’s common for them to fly apart. If you look at your tires wright where the tread meets the sidewall you will see a very small ring that goes around
the tire . That ring and D O T tag will tell you it was a retread. My trailer was brand new with less than 2000 miles on it. Hope this helps you.
For safety everybody should check there tires and wheel hubs everytime you use your trailer . YOU NEVER KNOW.