Audio: Pitch Changes When I Zoom In - Why?

Hello,

I have an object that plays a sound over and over again (audio source) but when I zoom into the object in game play fast, the pitch changes until I stop zooming in/out.

Example: Object is far away - I can faintly hear it. I go to zoom in, and whilst I'm zooming in, the pitch goes higher, until I stop zooming, the pitch goes back to normal.

Example 2: If I dramatically zoom in and out continuously (scroll wheel) - the pitch keeps bending - zoom out, the pitch goes negative ... zoom in, the pitch goes positive.

What is causing this? I assume its a setting in the Audio Source?

Thanks.

EDIT: Forgot to mention that the volume gets louder when I zoom in - which is suppose to happen