Hi Inga,
Did you update BuddyPress to its latest version? Major changes have been made to this plugin causing this page bug.
The good news is that your issue has been fixed in the latest version of Gwangi. So, updating your theme will probably solve this.
To update your theme, you can download and install the Envato Market plugin (https://envato.com/market-plugin/) on your WordPress site.
Once the plugin is installed and activated, go to “Envato Market” in your admin menu and follow the instructions under “Activate Envato API Connection”.
When this is done, you will see your purchased themes under the “Themes” tab and you should be able to update your Gwangi theme from there by clicking the “Update available” button. If the update fails after clicking that button please try to click it again and it should work properly.
Regards,