Sound bug: different buttons make the same sound

I encountered the same problem too. in my program, there are 4 buttons corresponding to different animals. Supposedly, when a button is pressed the correct animal sound is played. But I noticed that when I reached the 4th button and press back again button 1, the sound played is now the sound dedicated for the 4th button. Same goes when I press the 2nd, and the 3rd button. It seems locked-up

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