Engineered when? Just because they can send information and travel faster than light doesn't mean that the light from there has reached federation space. A survey would have to have been done nearby to see it
Now, while it's quite away from the Federation, the system sits in or close to Romulan space, so it makes zero sense for it to be a mystery that only the secret police inside the secret police of the Romulan Star Empire knows about it. I mean, it's like suppressing the existence of Mount Everest from citizens of Nepal. I can't imagine how strong the intelligence/counterintelligence apparatus would have to be to actually pull it off, given most people in that country can probably see it with their bare eyes on most days.
(And of course this only matters for real-life telescopes; Star Trek sensors work FTL (except when it would have inconvenient consequences)).
Engineered when? Just because they can send information and travel faster than light doesn't mean that the light from there has reached federation space. A survey would have to have been done nearby to see it