A source with no box-sized area clear of transparent pixels (a small
layer inside a blur's padding) got no sample boxes, and
grain_stats_boxes then measured the whole image, edge included. With no
clean box Match Grain now matches no grain, as After Effects applies
none when its samples hold transparent areas. Compensate for Existing
Noise took the same route through the layer's own boxes, so a layer
with no clean box now has nothing taken off. grain_stats_boxes keeps
its empty-list fallback.
JonRC
1b5c28ee1d