Why do I hear static noise on my left ears when in AMB/NC?

When I connect and listen to music on NC/Ambinet mode for the first 30-45 seconds I have no issues and my headphones work perfectly fine. But after the first 30-45 seconds, on my left ears I start hearing static sounds on both NC and Ambient mode. I’ve followed all the steps on Sonys website to fix this issue but it’s still there. If anyone can help, I’d really appreciate it. Thank you!