Inspired by this answer
This answer does seem attempt to answer the question, but is unfinished when posted (although it did got edited after I reminded the author).
Left as is, the question will fall to Very Low-quality, which is unsalvageable. However, it might get edited if we remind the author (as he did in this case).
Q: How long reasonably should we wait before flagging it? 1 hour? 24 hour? Or should we down-vote and retract it after edit was made?