Interesting sound design

When Tetsuzo first meets Oei in the streets. She doesn't say much, and just keeps sucking on a little green candied plum. But whenever she bites into it, we hear a staticky sound, like the speaker was cracking or something. At first I thought it was a mistake. But then, throughout the rest of the film, whenever she's sucking plums rolling her eyes, we hear the same sound. Made me think it was creative decision. Not sure what the significance of it is.

Another incidence of this strange sound design was when there was a shot of a cat yawning, and it made a very human yawning sound.

Anyone else notice this?