Exo targeting

[Mad Rubicant]

What determines where the timed Exogalatic strikes (Spirecraft and Golems, but mostly Fallen Spire) target? Because in a game I had going earlier (abandoned because of the exos), I had two ways in to my territory, both with a city on them. But the timed FS exos would only target one of the planets. That was fun, since I was splitting my defenses between the two cities.
See attached map. Circled in blue are Spire Cities, and the one in red is taking all the exo waves. Yellow is the path that all the exo groups take. They completely ignore the juicy city in the top left, which also got ignored by the exos while it was getting built.
So, my question: How do exos target, and is it intended for them to ignore everything but the first city?

[vigilo confido]

All I see is the exo galactic attack spawning from that 1 AI homeworld and simply going for the nearest spire city. That is how the exo galactic attacks tend to work in general

[Kahuna]

I'm pretty sure Exos and CPAs don't spawn on AI Homeworlds anymore. They used to but that was changed. They can spawn on any AI planet with a warp gate and will target irreplaceables and home command stations.

[Mad Rubicant]

The thing about this that was bugging me was that the Botnet and Spirecraft exos would target both my ingress points, but the FS ones only targeted that one poor planet. And according to the wiki article (how do I insert links?), the FS exos should target your cities as well as the home command station. I'll upload a save, if anyone wants to see what I'm talking about.

Also, none of the wiki pages say anything about how the faction difficulty affect the waves.