Hi,
This is issue with OpenSans fonts loading.
Quick fix is preloading required fonts.
In my case I put code below in the Ext.beforeLoad function in index.php
Note: My Ext.manifest is object (not String like 'triton')
Code:
/**
* @bug triton-theme: Layout is broken on *first* page load without cache. After F5 all looks fine
* @fix Preload 'Open Sans' fonts
*/
if(Ext.manifest.theme === 'theme-triton')
{
['OpenSans-Regular', 'OpenSans-Bold', 'OpenSans-Light'].forEach(function(font)
{
var link = document.createElement('link');
link.rel = 'preload';
link.href = Ext.manifest.resources.path + '/fonts/' + font + '.ttf';
link.as = 'font';
link.crossOrigin = '';
document.head.appendChild(link);
});
}