Icons not correct saved/loaded if the menu item is a view

If I add a icon to a menu item that comes from a view, the icons disappears after clearing the cache. The problem is, that the config key in fontawesome_menu_icons_form_menu_link_edit_submit() and fontawesome_menu_icons_menu_links_discovered_alter() is different.

The config_key in the submit function is in my example: views_view:views_offer_search_page_4
And in the discover function: views_offer_search_page_4.

Since the config is saved based on the config_key in the submit function, the icon for the view menu item is not found in the discover function.