A valid argument is often defined as one in which it is not

I honestly don't think it's worthwhile to ask, when looking at questions on this forum from unknown or unofficial sources, "is the writing here perfectly precise or is it ambiguous?" You'll find ambiguous writing all the time in unofficial questions, so you'll end up doing nothing else. This particular question seems aimed at an audience familiar with the basic definition of an 'argument', in the logical sense - as a chain of reasoning connecting premises to a conclusion. If you know in advance reading this stem that an argument's 'validity' is independent of the truth of its premises, you wouldn't be tempted to interpret it in the second way you suggest. I don't know where this question is from, but it reads more like a question intended for people preparing for the LSAT than for people preparing for the GMAT.