Hi @mindingyourmedia,
I checked your site in IE and I could not find the code being applied on the front-end, this could be due to cache as I see the content of your site is being served by the cache so you could be seeing the old cached content. Please clear all caches (plugin, server and browser) and deactivate cache plugins and optimization services.
Also make sure you add the suggested code in the Element CSS of the Navigation Inline element (see screenshot)
If the issue persists then please replace the code with the following:
@media all and (-ms-high-contrast:none) {
*::-ms-backdrop, $el.x-menu > li, $el.x-menu > li > a {
flex: none !important
}
}
Don’t forget to clear all caches including your browser’s cache after adding the code, I tested this one and it works as expected (see screenshot)
Hope this helps!