In the weekly update Bungie mentioned people had be having problems with ammo synthesis. I had this problem as well, and it was fairly frustrating trying to do the hard raid while not able to get ammo from them. With the help of my fireteam I discovered that having a full inventory stops any consumable from working properly. Once I got rid of an item from my inventory everything seemed to work as normal. While it's an issue that needs to be resolved, this can help while Bungie works to find the specific glitch.