You have to bear in mind that, when these were made, the vast infrastructure of robotic assembly we have now, simply didn't exist. Every single LED chip in these displays was hand-placed, and the wire bonding done manually, one connection at a time. Every other component on the circuit board was similarly installed, by human beings using tweezers and binocular microscopes. Allowance had to be made for human error (there are two bonding pads on each LED chip; sometimes you will see a wire broken off short on one, and the second one had to be used). Also note that this entire display sits conspicuously below the center line of the glass, due to a slightly-off-the-mark placement of the circuit board on the plastic carrier. Obviously visible tilts of the entire display to the left or right are also occasionally seen. This particular one happens to be a Monsanto display; similar manufacturing slip-ups also occur on those made by Litronix.
And yes, I have seen this same thing, on different digits, on several watches...an artifact of the primitive state of the art at the time. The LED chips were selected for color and brightness match by human eyes, chip by chip. Given the limitations of the technology, it becomes even more remarkable that Time Computer managed to produce more than half a million watches in just five and a half years.