HTML5 followed layout: the presence property (visible / hidden) not working on LC ES4 but working on SP1

[tarekahf]

I noticed that there is some improvement in LC ES4 SP1. See images below.

In a followed layout parent form, the child subform presence (visible/hidden) is work somehow OK on LC ES4 + SP1 but not working correctly on the same without SP1.

But even on SP1, still not working 100% correct. There page is split and after hiding the subform. See images below. Is there a way to fix this? Or this is just how HTML5 works in Adobe LC platform ?

The same form when run under LC ES4 without SP1:

The same form when run under LC ES4 with SP1: