Nougat mining mines to the edge of the construction area on the left edge, but one less than the area at the right edge. I hacked it to work: in nougat.chewy and nougat.register, you subtract 1 from the right/bottom edge. Which is obviously (by what the bots then do), wrong.
Classic off-by-one due to (from what I know of the API) docs that are not quite as clear as the writers think they are. :D
(Repost as bug…)