The non-uniformity is apparent in DN patterns of 2's, 4's, 8's, 16's and sometimes 32's. The ADC component is of the successive approximation design. Each band has 10 channels and each channel is a 12-bit word. For each individual channel in a band, it is digitized simultaneously with the correspond channel in the other five bands. Correspondingly each bit within each channel is selected simultaneously.
Little commonality is present in the patterns amongst the ten channels.
Consequently, the instrument feature appears to be driven by micro-noise at the ADC during the digitization process. There is no way to know if the current configuration is the best, worst or intermediate quality amongst the range of available cross-strap configurations.