If a question asked on CV is answered on another SE site, is that a duplicate question?
I found a "duplicate" question of yours and my answer here, as one example, will try to follow Eliah Kagan's answer hint:
He says (among other paragraphs):
If the question is not really the same, but just somewhat related--as is often the case, especially across sites--then it can simply be answered. An answer may use and cite some information from one or more answer to the related question on the other SE site.
If the question is really the same and on-topic, it can simply be answered with a link and quoted, properly cited excerpt to the other answer. It sounds like that's what should happen here, and it has.
There is no problem with this situation. You may get different answers due to having asked a different community. We ask that people not ask the same question on multiple SE sites. We don't ask that people not ask a question one one SE site that someone else once asked on another SE site.
It is not an official answer on Meta Stack Exchange (i.e. posted by a community manager or moderator) but it is well upvoted and by looking the comments here I think we also agree with it.
Just remembering we are not talking about cross-posting (the same question by the same O.P.) as also mentioned by @gung and @chl.
Cross-website duplicates waste the efforts of the community. I think the answer is: Build and strengthen the Stack Exchange community with "crossover questions" between sites. That would be extremely useful in the CV vs. data science case since there is a huge overlap between these two websites.