More than likely strain related. Not all plants react the same way. I had a strain never brown up until about the 3rd to last week of flower, then she exploded with orange/brown everywhere. Some just do it earlier then others. It’s also believed to be that pollen has entered your room and that’s a cause of the browning early in flower. Just check her underside and make sure you don’t have any sacs. I’m not gonna route that possibility out, but I would look just to make sure you done have a hermie and she isn’t pollinating herself.