Here is one example (maybe not the best) of a question that morphed, through editing, from one question to another, as people tried to answer it.
That does not help SE or its users, as it discourages people from helping (answers).
Should it be a reason to close a question? (Yes, it is a judgment call, because some morphing is reasonable (and helpful), as a user tries to clarify a question.)
Or should it be handled only by downvoting (because the question was not very clear)?