Never known Linux to get any sort of bug and it seems unlikely that Antergos (or rather Arch) would be targeted out of all of the distros out there since most people who use Arch (or anything based on it) have a reputation for being extremely techie, and thus harder to fool with a mere scam. Think about it: if a group has a reputation for being able to live their entire lives in a terminal and even browsing the internet in it, (yes, that is actually possible) do you really think that they are the best candidates to try to fool with a mere scam??? They could probably get rid of your scam (if they even got it) quicker than you yourself could! In fact, they are probably better coders themselves than you are!
That said, I do agree that it seems rather fishy. I would personally ignore it and contact one of the @developers about it as soon as possible. They of all people would know if it is legit.
Anyways, perhaps it is a virus from Windows 10 that got onto your computer and has an algorithm that allows it to detect the name of your OS. That way, no matter who it hit, it would look like it was intended for them.
NOTE: if you plan on contacting one of the @developers, I would personally contact @karasu since he will probably answer your question the soonest (before you forget and accidentally hit the weird “antergos-alert”). If it helps at all, I have never gotten this alert, so it definitely isn’t being sent out to everyone on Antergos.
Hope this helps!