Existing Groups not displayed on [agm_groups_map]


I just purchased your plugin, and I am trying to view all groups on a map using the [agm_groups_map] shortcode on the testpage http://www.airsoftdb.nl/grpsmp/
Only when I create a new group, it get's displayed on the map. Updating the adress for existing groups doesn't add them to the map.
Could you help me with this?

Kind regards,

Herman de Bruine

Wordpress 4.1.1
Buddypress 2.2.1
Google Maps
PHP 5.3.10-1ubuntu3.5
MySQL 5.5.29-0ubuntu0.12.04.1