I had a very curious experience today -- had an AI revolution event (very late stage of the game, half of galaxy under my control) which spawned huge hordes of ships(hundeds of battleships & cruisers). For comparison I had two 40k fleets + Gray (~40k) There were 3-4 groups of ~200k strength, plus few smaller ones. And my fleets were scattered all over galaxy...

They got only few systems at start. I started to scramble, designed "anti-them-build", kicked off shipyards construction behind front lines, etc. But after few days suddendly these 200k groups turned into 50-60k and split into smaller groups with some of them having between 29 and 120 strength (yes, no "k") even though they have bunch of battleships. When I look at these ships it shows negative avg damage. When attacking them they melt like wax. And yet there are couple 60k-strength groups that fight like I would expect them to...

Is it a bug? Result of having no resources for ship maintenance? Holograms? O_o

I've attached an example:

...weird. Felt like their entire space force was crumbling apart while running toward me. Like buggy AI. Wiped them out real easy. Now I wonder if I should stop genocide of their pops...

P.S. Hardest part was to take my 2 maxed out citadels back (they were taken away during event)