Any of the Invasion (INV-XXX) fleets, Assault Fleets (ASF-XXX), or Raid Fleets (ASR-XXX). Basically anything carrying troops. Sometimes the attack fleets (LAF, MAF, or HAF) will go after something they shouldn't (like blockade a planet), but it's harder to tell and rarer.

I'll try to give the ...

No mods. I did make use of the map editor in the beginning of the game, but that's it. Again, the problem only started showing up after I'd gone to war with someone.

It's very reproducible. As I said, just letting it run for a bit will see multiple fleets assigned to invade planets I'm not at war ...

I have not tried it on the beta release, no, sorry.

How far back would you like me to go?

Here's one save from a few years before this instance, but I believe after my first war with the Dhayuts: https://drive.google.com/file/d/1aaCfW_v6i_tXW040Wwlfs8kC_6BbilJf/view?usp=sharing

Here's one a ...

Save file (zipped) is here: https://drive.google.com/file/d/1h_uLBq ... sp=sharing

Running the latest version.

Attached two screenshots.

Top two fleets were previously loading troops. When that mission finished, they automatically set themselves to invade a planet.

As you can see from the SS's, that planet belongs to someone I'm at peace with (I was at war with them recently).

This didn't happen prior to ...

I do, though I get "file too large" for including (save file, zipped via 7z, is 26mb)

It has made my game practically unplayable, as the problem is just getting worse. Fleets are wanting to invade allies, and my ships are attacking unaffiliated ones. Unless I set everything to manual - which is not tenable - my reptuation gets tanked, and my relations sour (I went from +55 down to ...

I recently ended a war that had multiple combatants. I'm now not at war with anyone.

My Attack/Raid/Invasion fleets are continuously trying to invade other planets, though, belonging to allies, as well as those I was last at war with.

I don't have a planet in the system they're trying to invade ...