Font Awesome vanishes when using advanced layout builder

Hi.

I read the thread by @Yigit on how to enqueue font awesome icons in the function.php file, but I have noticed that when adding the code snippet

‘<i class=”fa fa-desktop”></i>’ (same for all other icons)

using the Advanced Layout Editor – that after updating the page, the icon snippet vanishes from the page…. not sure why this is happening and wondered if this is something you guys know about?

see screenshots below that demonstrate my issue:
– adding the code >> http://snag.gy/LEMoY.jpg
– confirmation the code was updated >> http://snag.gy/xrNky.jpg
– after page is updated, the FA is visible in the Advanced Layout Editor, but when I click on the Text Box to add something else, the FA code snippet is now gone >> http://snag.gy/jQ2wJ.jpg

any help you can offer is greatly appreciated!