Aye, previously it was rendering the Font Awesome character code as "???" but now the correct unicode character for the FontAwesome Font is loading... it's a very popular library so I wonder if JCH has any workaround perhaps...
This is the selector:
.g-main-nav .g-toplevel>li>.g-menu-item-container .g-menu-parent-indicator:after
The theme CSS all loads in: /templates/rt_reiko/custom/css-compiled/
... if you want to have JCH ignore that.