It may not be outright stated, but unless the Shivans were actually plotting a Xanatos Gambit involving the possible capture of the Taranis(putting beacons on it just in case?), I think it's a little unreasonable to assume the Shivans did not then have the subspace technology/expertise to track large ships just as the Ancients did 8000 years prior.
IIRC, subspace tracking requires one to be there while a ship jumps out. You have to have a sensor/scanner/ship in the area.
It is possible there were shivan ship on the Ribos side of the node that tracked the transport hauling the Teranis.
Perhaps, but also let us remember the Shivans subspace tracking MAY be far superior to the GTVA's, and not subject to the same limitations. Conversely, it could be inferior, but I find that unlikely.
As for this argument over 'for the lulz', NGM is definitely right. We don't know why the shivans are xenophobic maniacs we just know that they are. Maybe they evolved on a planet where the only possibility of survival was to crush anything approaching your intelligence, and thus by definition, a potential threat.
Or maybe our use of subsace is bad for them (cus of their 'sensitivity')
Or maybe they are megalomaniacs and just do it 'for the lulz'. We can't know, we don't know, but all theories are just as valid.