The object flew through our solar system a a velocity consistent with other stars in this part of the galaxy. This suggests it is just drifting along with the rest of the local spiral arm stars.

There is a concept in stellar kinematics called the Local Standard of Rest (LSR). It refers to the average speed and direction of stars in the solar neighborhood, and it exhibits a speed and direction due to orbital motion around the galactic center, about several hundred kilometers per second relative to the galactic center. Most of the the stars in the galactic disc within a few hundred light years share this general velocity, implying they are all part of this general rotation.

There are some exceptions to this rule, the so-called "high velocity" stars, a population of stars which orbit the galaxy in random orbits, not as part of the disc population. These stars are part of the galactic halo and we see a few of them flying through the disk at odd angles and high speeds. This population was probably formed during the early history of the galaxy, while the disc stars (like our sun) formed later after the disc stabilized. These stars all seem to be traveling at several hundred km/s relative to the LSR, so from our perspective they seem to be "high velocity"

Most of our neighbors, flowing along with the general drift of the LSR, all appear to be moving at relative velocities in the range of several tens of km/s. This is a minor motion superimposed on their LSR velocities.

The two interlopers we discuss here have moved through our solar system at velocities consistent with LSR objects, plus the little extra speed they might have picked up by falling down the sun's gravity well. We know they are outsiders because they are moving faster than the sun's escape velocity, but still at LSR-typical speeds.

It seems unlikely an extraterrestrial civilization would bother launching probes at the same rough velocity as the drift itself. Then again, who knows? Maybe the aliens are in no hurry to get anywhere.

https://en.wikipedia.org/wiki/Stellar_kinematics