On the other hand, I logged in 2.4 at Palin's base, no sign of alien activity.
Flew to Darnielle's Progress to check whether they have meta alloys, making sure to check all USS along the way. No sign of alien activity.
So I went back to bubble to continue on the Eurybia CG, still no sign of alien activity.
Maybe some players see it but so far it is definitely not obvious. Or it's random as usual, some players get multiple alien encounters while others have none.
Have you looked at a single USS on your way? Space is flooded with non-human signal sources in the Pleiades and there are consistant locations all around as well.