Sadly in some layouts, we have this problem, the header seems to flash glitch, or jump. I got crazy searching for something to fix it, until on some random forum website I found this code (you need to paste it in Divi > Theme Options > Integrations > Paste it on the header:

<!– Fix flashing Divi header –>
<script type=”text/javascript”>
var elm=document.getElementsByTagName(“html”)[0];
elm.style.display=”none”;
document.addEventListener(“DOMContentLoaded”,function(event) {elm.style.display=”block”; });
</script>

That´s all!