Why does my cheese has brown spots on it sometimes??

Thanks for the reply. We have one deck oven and one rotary oven, both gas. We only make pizzas with room temp dough, not cold unless we get a un-expected hit. No matter what oven, what temp, what top heat setting and what temp of dough some of the cheese will brown and some wont EVEN if it comes out of the same bucket. So today I received 100 lbs of Grande to play with and so far NO browning at all! I made about 4 very well done pies today for customers and some very small spots of brown which is totally acceptable. I seriously think our cheese manufacturer of 25 years has changed quality :frowning: