According to this article the US Army (more likely the brass or bean counters) has decided that the Magpul PMag is persona non-grata for their units in the field. Neither the Army or Magpul is willing to state why but I suspect the decision has nothing to do with Magpul’s product.
I will admit to being one of those who scoffed at the product that started Magpul Industries into the company it is today. I have since found their gear to be first rate and their representatives to be friendly courteous and willing to listen to their customers. When they came out with the PMag I picked up a couple and gave them a run down at the range. Then I bought a few more and a few more and will continue to buy them until something better comes along.