Today I was in the local Apple store browsing and tried the new iPad Pro - the screen is superb and based on the same tech as the MacPro’s display. However, I was surprised to see that the image background to my container plus stack was zoomed to extreme and nothing I could do would render it normally. I use a few of these stacks on various sites and have seen no issues on any platform, until today: https://wildphotographer.co.uk
Naturally, I then wondered around trying the image on all the other accessible devices and everything was rendered normally (including my own iMac 5k and old retina laptop).
The only other problem I have seen with any of the STH stacks is non-visibility of Parallax stacks on some windows devices, but it is not a market that worries me.