It may occur that a new player is created in an event rather than selected from the player list.
In this case a duplicate player profile has been created. This is easy to fix.
Please contact your rating system owner who will then merge the profiles. After merging the system will re-process ratings to take into account the merged rating.
If the original player cannot be found because the names are recorded too differently, update the name of the duplicate player so it's a closer match to the original player. This will make it easier to find players to merge.
Always merge into the player with more rated events.