In the attached image, it shows two logins and a command ran upon entry both times. The first time, as shown, the plugin returns that the player has not played before. The second time, done after reconnecting, shows that the player has played before.

This is a major issue in some cases, as many plugins use this to decide whether or not to save a file. An example is shown in a plugin called "EasyChests." It does not save a new player's chest, as hasPlayedBefore() returns false on them.