I have an Instinct Crossover and am currently porting over some of my watch faces for it. In simulator if, for example, I remove a mask I have in place for burn in protection, it triggers the File>View Screen Heat Map interface to troubleshoot. Otherwise, View Screen Heat Map is grayed out. And I was able to successfully test my watch face on my Crossover AMOLED, with burn in protection of course. So I would say it's a simulator issue.