On some phones sounds are started with an increasing volume if sound comes out of the phone speaker. This often results in a stuttering or distorted sound. Moto phones for instance are known for this.

As of version 3.2.5 you can choose which audio channel to use for sound output in the settings. Playing the sound as notification or music might help.

As of version 3.2.6 you can alternatively choose to use sounds beginning with three seconds of silence. Either by using your personal sounds. Or by enabling the corresponding option in the problem solving section of the settings.