There was no indication that the decoding of MS was an issue. The digital output was merely the inverse polarity of the input.
Phase issues with MS would result in swapping Right & Left. (I don't decode on the fly, so I record a brief message to myself to insure proper R-L orientation on decoding) This typically comes from the side capsule being oriented in the wrong direction.
With proper inputs Mid on Left, and Side on Right (badge facing right), the V3 will properly decode Left and Right channels, but still output them as the inverse polarity at the digital outputs.