We are sorry for the inconvenience you're experiencing. The issue will occur due to the microphone capturing sound during the VoIP call. When music is playing, the microphone on your device can pick up and transmit the sound along with your voice, especially if the microphone is positioned near the speakers.
To avoid this, you can lower the volume of the music during the call, or pause it while talking to the other party. Use a headset or Bluetooth earphones, as they help isolate the microphone from external noise. Please update your phone to the latest OTA version. Thank you for your understanding!