As I noted in my suggestion thread pirates are spamming armadas in player colonies under certain conditions.
I had hoped that after killing the ten fleets that would be it since they seemed to stop at first, however the issue is persisting.
So far upon each of my visits to my colony I've had 10 fleets, 2 fleets, 8 fleets, and now 3 fleets just in hyperspace I haven't entered my colony yet due to the extreme number just outside.
All of which are armadas, as in there are no scouts, raiders, attack fleets, etc.
The steps to reproduce are following how I played during this run.
Let the pirates develop for about a decade, destroy all pirate stations near where you want to set up. I destroyed one before colonization.
Colonize several planets at once, I colonized six, three admins and three under my control.
All planets should be at five or less stability.
Build a waystation and industry on all planets.
Destroy new pirate station that spawns near your system.
Return to your colonies a few weeks later and find a large volume of pure pirate armadas.
I know this isn't an overzealous feature to try to get the player to negotiate with Kanta as I'm resetting my hostile activity bar to 0 every time I clean out my system.
No rush on the fix, while it's tedious I've played through worse. Currently I have a high command set up, and am generating nearly enough cash to break even each month, so I can theoretically keep it up until every planet in my system has a star fortress and high command.
I will upload a save in this thread if you can't repeat the bug on your end, just let me know what file service you want me to use.