Flex + fixed + inline + relative + add properties with animation 
the animation change your display from flex to block (This is “WHY” you see this layout) -
<div data-ix="airbnb-credit-fly-in" data-w-id="2012be35-06dd-b0f2-8c8f-648390e4dfa2" class="airbnb-fly-in-div-block" data-ix-affect="1" style="transition: all 0s ease 0s, transform 700ms; transform: translateX(0px) translateY(0px) translateZ(0px); display: block; transform-style: preserve-3d;">
i dont know if this is a bug but try to work with more simple code