There are many registered AIRDROP addresses in the list on https://bitcore.cc/airdrop.php?info=all but they do not show up in the blockchain explorer, e.g.: http://51.15.78.208:3001/address/1KSfk8Sishwc7UJqCGNd8yh8v3btxHRo54
Why is that? Is it a bug? Or is someone pumping the number of registered addresses? Or is it an empty address where someone plans to deposit?