In case of these specific NPCs that doesn’t matter.
https://wiki.eveuniversity.org/Drifters#Autothysian_Lancer
When engaged they usually warp in another wave of Autothysian Lancers but there is also a chance a drifter battleship will warp in.
Tip- Preliminary investigations show the Autothysian Lancers will continue to aggress you until they destroy a ship your character owns. If you accidentally engage them and survive the initial encounter board a cheap frigate and let them destroy it. Authothysian lancers cannot be scanned down but they can be attracted to your position if you enter within 50km of a Jove Observatory (only do this to sacrifice a ship). Once they destroy your ship that character will be cleared from aggressor status and you will no longer be targeted by roaming patrols. A frigate or larger ship is suggested as a corvette is not typically engaged by Autothysian lancers, even if your character is on their aggro table.
Also:
if you’re near a Jove Observatory or a Drifter Wormhole and Autothysian Lancers or Drifter Battleships show up
So if you’ve warped to an observatory site (that session or maybe even in the past not sure about the latter) maybe that was what triggered them. If I recall correctly they tend to follow you around even if you warp away.
Further info:
Seems to describe your situation thus it is likely you have aggressed or triggered them in some manner that session or in a past one.
Further reading:
https://support.eveonline.com/hc/en-us/articles/212103929-Autothysian-Lancers-and-Drifters