Add this to js/core.js around line 932 right after this:
jQuery(‘body’).on(‘tabsactivate’, function(event, ui) {
for(var entry in wpgmaps_localize) {
InitMap(wpgmaps_localize[entry][‘id’],’all’,false);
}
});

jQuery('.nav-tabs a').click(function() {
    setTimeout(function(){
        for(var entry in wpgmaps_localize) {
            InitMap(wpgmaps_localize[entry]['id'],'all',false);
        }
    },500);
});