I've noticed that there's at least one other person with this issue (name: banana). It's basically the same series of events.

The mod runs fine in the Infinities campaign until someone invades Gyndine, at which point it prevents any combat...and I mean anywhere. No fleet combat can be initiated but attempting to start a land invasion triggers a battle over Gyndine.

I have tried this as 4 factions and all get the same result after about 7 Cycles. I can enter the battle and either throw the fight or wait for the AI to retreat. However, this will bring the other fights that got back burner-ed flooding forward and locks me into a Doctor Strange level time loop of trying to Auto Resolve or Begin.