How did you create your phone layout?
Adaptive or responsive? What is your minimum width? I hope 320?
If you use a mac you can watch at "Developer" - "Change to Responsive Design":
I searched and found out that you use adaptive design. By default the page width is set to 380. But as you see for iPhone SE you would need 320 instead. I assume, that some elements are set to be be responsive in width and height and like this it could happen that elements "float" and some do not. But without a .muse, reduced to one page , we can`t be really sure.
Watch this as well: Width for Iphone 7 responsive breakpoint? and
I hope this helps?