No.
They are two different sites with different communities (general *nix / Linux folks and Ubuntu folks); the question was posted here and is on-topic here.
Many people seem to think that it's mandatory to organize questions on SE sites based on the "better fit"; while this is something one should think about when posting, as long as the question is on-topic on the site where it was posted is fine there.
On the intra-network duplicates proposal: while it's undeniable that some topics overlap (and that sometimes there are exact duplicates between the sites), no user from each community should be obligated to attend both sites (although many, as me, do); it's nice to have a single place to visit to ask for help / help.
This also would introduce complexity; what would have you done if there was a, say, BSD-specific answer on that question? Closing as duplicate would have made no sense. Should everyone look up all of the answers and see if there is an answer fitting Ubuntu before closing?
Intra-network duplicates have been proposed many times, expecially on Meta.SE, and never went through; IMO, they just make no sense, each community has its own value of Q/As and closing as duplicate across sites introduces complexity. I don't think we need that.
Also the problem is easily solvable by other means:
- If you were the original poster of the question on one site, feel free to post in on another site. It's your contribution (so you "own" it) and you deserve the reputation as well.
- If you were not the original poster of the question on one site, feel free to post it on another site as a CW post, with a proper attribution, as I did here.