[jcwilde]

Interesting... One further question: when does it recalibrate—is it opportunistically, when it is already running past the reflective strip (I'm guessing in-line with the black displaying), or every so often (after each image cycle)?

One workaround that could better hide the inaccuracy would have been to only have smooth colour transitions on the ribbons (including between black and white), as it appears to be a hard transition between blank and white that causes it to be so noticeable with the small positional error.