Spoke to Reese today. Great support!
The person I spoke with said you can snap the cam's off if you turn 90 degrees but that would be really tough to do. The bar would have a problem first. If the installation was bad it would tow bad; the cam snapping would be the least of my issues.
Bottom line is that they didn't have a good answer as to why it would snap. Again he thought there would be other issue before that occurred.
For what it is worth I had to buy a wrench big enough (1 1/8") to be able to get the hitch off the truck and move it up 4 inches so the trailer wouldn't bottom out. I know there are bigger wrenches out there but that is the largest I've ever owned. It will now sit in my tool box never to be used again!
I bought a replacement on etrailers but I had to buy a pair for $138 (Reese confirm that they are sold in pairs). You do not have to replace in pairs but they are sold that way. I saw it for sale on Amazon for $92 but it said "Usually ships in 1 to 3 months". MONTHS!