I have had my Pit Boss Pro Series for about 5 months. It was producing awesome grilled chicken breast, hamburgers and steak. About 2 months ago I was grilling steaks. I could smell a horrible plastic burning smell. So bad, it ruined my tri tip! The last 2 times I've used it, same thing. Today I changed pellets, cleaned and burned it out for a few hours. Chicken was looking good then the smell and a weird slimey smoke haze over the chicken. What is it?