Hello csalsb1017
I had this same problem about a month ago.
I contacted nap and they told me to send it in and the would either fix it or send me another.
Instead I took it a part and found a small cotter pin that had shired off. The purpose of the pin is to stop the prongs form moving out of its range of motion.
NAP said the cabel connected to the rest is to tight and was putting to much tension on the pin causing it to break.
After pushing more of the pin back into place and looseing the cable I have had no more problemds with the rest.
I hope this helps.