I'm using the 12b14b encoder/decoder in a circuit and when I simulate I see a single disparity error out of the decoder which I can't explain. The disparity error occurs after several hundred clock cycles even though the decoded data is correct. My testbench applies a test pattern into the encoder which consists of an incrementing 12bit count value.

Have you seen this problem before? I notice a comment in git about a fix for the disparity function saturating its value. Can you please tell me if the Encoder/Decoder vhdl (attached) which I downloaded from the git surf directory are the latest?

To debug this problem, I created a small testbench (tb.sv in the attached file) which is simply the encoder connected to the decoder with an incrementing count as the data input. This testbench does show the disparity error.  

Thanks,
Mike