i just realised that this theme is jumping a few pixels (maybe 20px) up or down on about every 2nd scroll on mobile phones. i saw that on my own test-site first, and it also happens on your incline demo itself.
i tested it on a samsung s6 with the browser that comes with the phone and also google chrome + on an iphone 6 with the safari browser. this happens with all the 3 tested browsers... it's quite annoying. do you have a fix for that?
edit (to maybe be more clear):
i scroll with my finger (either up or down) and "let it go". the site stops at some point and then after it already stopped it immediately jumps approx. 20px further up or down. this happens at least on every 2nd scroll in all the tested browsers on android and iphone (with my own test-site and with your original demo as well)...
i just saw the same issue with another wordpress theme that is not from shape5. i thought it might be the lazy load feature but it's not...