Currently autoscale puts instances into rotation without checking if the actual application is warmed up. Please add a feature to autoscale that checks if an application is warmed up before its put into rotation. Noting that the new Health Check feature has capabilities to detect bad instances based on URL (this is different than adding new instances with autoscale) this may be start as you could queue off the URL to hit in the app to know if an instance is ready to be in rotation.