I also seem to be getting an odd bug with Precursor Anomalies. In Kennedy V1.4.1 build (1759) with the Leviathan story pack installed, I keep getting popup messages about discovering evidence of a precursor race, the message you receive after you succeed at scanning an anomaly. In my case being the Vultaum. These messages are stating that it has been discovered on -------- planet with the click box saying We should look into this, or something similar. The planets that keep showing up in these popups are planets I have already surveyed hours before and nothing shows up in the situation log. Now, I have been scanning systems further out in the galaxy and found 4 others sites before these started popping up, but now, after scanning over 20 systems, I am no longer getting any precursor anomalies other then the message that one has been found on ------ planet in a system I have already scanned hours earlier. Due to this, it seems I might not be able to finish the precursor chain. Before installing the Leviathan pack I did not have this issue.
I do still get other anomalies normally so those still work.