This doesn't resolve your problem but, by way of explanation for why not everyone sees the lightning bolt:
The forum software platform is XenForo, is it not?
The lightning bolt symbol is a navigation icon to provide quick access to new content. It’s a space-saving feature for mobile devices with small screens, replacing the “*What’s New” drop-down menu used for the desktop version of the forum where there is more screen space available.
If you’re using a mobile device and don’t see it, that’s probably related to your device’s display size or custom font size/zoom settings you're using. If those have restricted the available screen width, then the lightning bolt may be hidden inside the expandable main ‘hamburger’ menu icon, or dropped altogether. Sometimes, if you turn your phone sideways to give a wider screen, it will pop back into view.
Depending on how the forum has been set up, XenForo usually defaults to only showing the icon to registered users who are logged in (as an encouragement for guests to register).