In Cadbury system, many years ago, I detected an alien ground force signature.
No population, no ships, just a small ground force signature.
My geo survey ship completed the survey without incident, and found alien ruins and a potential for a geological surface survey.
Unafraid of the ground forces, I sent in xeno troops (non-combat), and after a long time they completed their work and identified the ruins: a small site with just 7 installations.
I then sent in construction troops (non-combat), and over a period of many months (maybe years) they completely excavated the ruins.
A long while later I sent in geo survey troops (also non-combat). They worked without incident for more than 3 years.
So, for many, many years, I had troops on the surface of this planet, and never had an incident with the alien ground forces.
I could still detect the signature, but otherwise there was no sign of them.
Just now, in Mabel system (5 hops away), a geo survey ship of mine was attacked and destroyed by unknown ships.
At the exact same time as this attack, the alien forces on Cadbury attacked my troops there (to disastrous effect for me, since mine were all non-combat).
I see no logical reason for the Cadbury aliens to suddenly become hostile to my non-combat forces because of something that happened five hops away.
So I'm reporting it as a bug. If this is WAI I can accept that, even if it is kind of a head scratcher.
DB is attached.