Weight distribution torsion bar bolt snapped

Pictured is what my weight distribution hitch looks like.

My problem, I had thought that the bar was locked on the hitch receiver.

While driving down the road I heard something dragging.

As I pulled over to investigate, I heard the 'ping' of a metal bar bouncing on the concrete.

Apparently, it wasn't locked in and I broke the bolt that is cotter pinned to the A frame of the camper.

My question: Has this happened to anyone else? What bolt did you use to replace the broken one?

I haven't looked at the information booklet on the hitch yet.

We just got back and I regular towed the camper for the trip.

Definitely can feel a difference on the tow.

Thanks,

Tom