While we're currently closing in on the presumed Stargoid, I'd like to put the question forward "From where does it come?"
There are no known Thargoid structures anywhere near Slegi JD-W b46-0. The next Nebulae, Soul Nebula and Heart Nebula, are several thousand lightyears further away. So far the working theory was that the first Stargoid originated in the "core Thargoid sectors" somewhere in the permit locked sectors in and around Barnard's Loop. This second Stargoid is coming in from an entirely different direction. A region of space, that does not have ANY indications of previous Thargoid presence.
Further, given the speed of these things ... it either originated relatively close to its current location, or it's been travelling for a fairly long time to get here.
Possibly it set off from GS-X b45-0 yesterday and no-one detected it before that because it wasn't moving before that. [1]
Even if it set off when the Proteus Wave went off, then it still probably originated within a few hundred LY of its current position. So there's no permit locks this time, it'll probably be more practical for people to backtrack that cone and have a poke around.
And if it set off before then (months or years earlier if it came from Heart&Soul or Bovomit or anything else obvious out this way) ... why are we only detecting them now?
We'll get a better idea of where it's going and therefore where it might have come from after it's been tracked for a couple of weeks, but there's nothing obvious anywhere nearby on the map, and it's low enough below the galactic plane that this doesn't seem like a place you'd go "through" either (despite Slegi being on the Formidine/Eafots route, this bit of the sector is much more poorly explored) on your way between two more interesting places.
[1] This is probably the scariest possibility, as it means that "sleeper" stargoids could be scattered throughout the entire galaxy - parking them stationary a few LY away from a star would make them entirely undetectable even in well-travelled space while not being at all inconvenient for them - in areas we've never considered as likely for them to be.