Theme Icon Fonts problem - just show letters no icons

Hi ...Please take a look, https://www.dropbox.com/s/8tcohs5kb0xh6p2/iconfail.jpg?dl=0
is this normal? since I only have few icons to use on the editor.

I think this is related to my problems of missing some icons on the page https://premium.wpmudev.org/forums/topic/anyone-know-what-happened-with-this-my-post-list-seem-very

how to fix it to work on my fixer theme :expressionless: I feel the irony.
and is there any options to changes the icon with 'icomoon' which is already on the upfront/font folder? or anything that just put on the simple custom CSS.

Thank you!