Edited changelogs with a note that got left out:
- Invasion disruption time reduced if defender's damage that round exceeds attacker's
I think your balance may need some changes. I have one size 4 colony and just got wardecc'd by the Sindria/Persean alliance and invaded. They sent across 5 fleets:
9 Conquests
6 Victories
4 Chronos
7 Triumph's
Plus assorted cruisers and others(including enough venture's to blot out the sun) I'm in the process of trying to beat it the main issue being CR and insufficient ships for me to fly of sufficient firepower to keep them from gutting my star fortress. But this is a bit overkill for a faction with only one size 4 colony to its name.
That sounds like it shouldn't be happening, except from two invasion events at once (and even then not for a size 4, except under certain circumstances). Is that's what's occurred?
(Generating an invasion fleet from Kazeron to Jangala (a size 6) with a new level 16 character gets me 9 Conquests (and 7 Atlases))
If you like, I can look at your save and see what factors (intended or otherwise) are resulting in those fleets.
In the meantime I'll change the opportunistic war declaration a bit so some "nicer" factions require worse relations to do it. That won't help with Diktat, but I might also change the alliance vote logic so Perseans won't get also pulled in if they like you enough.