Just installed and activated this in a fresh (localhost) install of WP 3.6, using the 2013 Theme, and entered 2 events (each at a different location). In the "Locations" page each location is (incorrectly) displayed twice. Checking em-locations.php, I found that count($locations)== 4.
1) Deactivated all other plugins and retested - same result.
2) Played with various settings to the Locations page - same result.
Any idea how to solve this?