Analog Jitters with the DRI0023 stepper driver

Hi

I am using the earlier version of the DRI0023 Stepper shield to run a stepper motor.
I am using it on an Arduino Uno, one bipolar stepper motor is attached, and the stepper shield is powered externally with 12v.

I am using analog ports A0 and A1 on the Uno to measure positions, each are connected to 10K linear potentiometers.
The motor is working fine and stepping perfectly, but the issue I have is that the analog inputs fluctuate badly whenever they are connected to either the stepper shield or the Uno itself while the stepper shield is connected.

If i remove the stepper shield, the potentiometer readings stabilize again

The potentiometer cabling is shielded, and the analog inputs are rock steady without the stepper shield mounted on the board.

I have tried another Arduino, another stepper shield, different analog ports, all with no luck.

Is this a known issue or it there something that can be done to resolve this.?

Thanks