Balance question regarding PROFICIENT M40 Receiver

When I am playing the receiver and I turn the balance control to the left...there is no audio sound.
 However when balance is placed in the middle, the full stereo sound is on both channels.
It Sounds normal.... both channels operating as they should.
Should I ignore this quirk and just play it with balance in middle ?
Any idea what the problem is and can I correct it ?
Are you sure you're hearing stereo?
This same thing would happen if both speakers were connected to the right channel.