Jonathon I had an issue with a mushy grind. Upon taking the grinder head apart I discovered lots of fat stuck to the grinding tube, plate and cutting blade. It was actually frozen to the metal surfaces. I cleaned up everything and let the grinding head and all parts warm up for a bit more than 1 hour. Before starting the original grind, I had put the grinding head and all parts in the freezer for more than three hours.
I had set the meat back in the fridge while I was cleaning up everything and letting the grinding equipment warm up a bit. Commenced grind again and everything was as it should be. The theory I developed for my self was the grinding metal was so cold that it was freezing on to the metal surfaces and it clogged up and was turning to mush. Kind of like putting your tongue on a piece of frozen metal. I would not claim that this was 100% the problem, but it worked for me.