The temporal averages accumulated per-scene edge junk into stable margin
artifacts (ROWCOL-04: worst columns x=12,20,28 = 8-px tile pitch -
partially covered virtual tiles at the warped-coverage edge; the wobble
sweeps which tiles are partial). For the two AVERAGE slices only
(individual scenes stay liberal/untouched): each scene's contribution is
box-eroded 24 px (3 tile pitches, AVG_EDGE_ERODE - clears the
partial-tile ring) and outlier-rejected (3 sigma vs the first-pass mean
when >= 4 providers, per Andrey's >1-non-NaN-provider rule); zero eroded
providers -> honest NaN.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>