QML Advanced Tutorial 4 - Example - Highscores are doubled

Description:

Highscores are entered twice.
Steps to reproduce:

1. Open the QML advanced tutorial 4 example
2. Click on the "new game" button
3. Play the game until you finish it (score does not matter)
4. Enter your name for the highscore
5. Highscores will be shown (Your new highscore should be there)
6. click on "new game" and play it again
7. Enter another name for your new highscore
8. Your old highscore will now be in the table twice and your new highscore will be there only once (it will be there twice, when you will see the highscore table again)

Expected behavior:

Highscores should appear only once.

Observed behavior:

Highscores apear twice on the highscore table.
Special notes:

Highscores seem to be added when first entering the name and a second time when opening the highscore table again.{}