Somehwat bizzare issur with pitch changing in garageband?

Somewhat bizzare issue with pitch changing in garageband?

So basically whats happening is I record a vocal track through a usb interface with the track in stereo, and then switch it to mono so that you can hear the vocal on both sides.
However, once I change the pitch (up or down, regardless), you can't hear the vocals anymore at all. If anyone knows what could be causing this, your help is greatly appreciated!

- Eric

Nobody?
This is in the latest version of garageband, its whenever I change the pitch the track volume goes too low to hear