audio - Weird waveform when using potentiometer as volumecontrol

I am making a remote volume control for my TV, as my amplifier only as a physical button. My idea is to control a digital potentiometer with an microcontroller. I have build the circuit shown on the follwing figure:

^{simulate this circuit – Schematic created using CircuitLab}

The potentiometer shown is a MCP42100, controlled with the microcontroller. As it is for stereo, two of the circuits is used.

When the volume is full, the signal is as it needs to be, when feeding it a sine signal.

However, when i use the potentiometer for attenuation the signal, i get a signal like this:

I do not understand why i get something like this, as it is just passive components and a voltage follower.

The parts: C1, R1 and R2 was added, because i had a signal like this:

This is clearly some kind of clipping, so i added some biasing, which works. Even through it works, i do not understand why, or even why it is needed as the only component the biasing is connected to is the potentiometer.

I suspect that this is coursed for the same reason as the other problem.

I start to belive that the potentiometer is at fault, but i dont know how. This is the datasheet i am using for the potentiometer: http://ww1.microchip.com/downloads/en/DeviceDoc/11195c.pdf

Can anyone tell me what i might fail to see?

Answer

Here's one potential reason:

You're sending an audio signal with a +12 V DC offset into an IC that is designed for much lower voltages.

EDIT: Here is brhans' solution:

^{simulate this circuit – Schematic created using CircuitLab}