May have been a non-aggression pact but I have seen more of this behaviour: two AI fractions at war with each other separated by my territory sending armies at each other across my lands constantly.  It rapidly gets tedious constantly ordering them out only for them to try and try again until they get over half way, then get a free move the rest of the way when ordered out.  I let them do what they want in the end.  They had no non-aggression pact with me. If this is how the AI behaves towards a player then why would they act differently towards another AI fraction?

There is strong evidence that suggests that the AI has been set to cheat in a effort make for a more challenging game.  But isn't it true that if your opponent cheats, then there is no game?

I was stronger than both of them added together, so that wasn't it.  They threaten to declare war if you order them from your territory, but never do.  Expanding my territory to deter them didn't work either.  The two remaining AI's had tunnel vision for attacking each other.  I left them to it and cast the spelling of summoning to end the game.

...

Because the AI has been re-set, to cheat like crazy in v0.913 !  It does so in numerous ways, several of which have been identified and documented in the current feedback thread on v0.913.

What is worse, is that the AI not only now cheats like crazy on the Challenging and Hard levels (which could be argued, as acceptable), it also cheats like crazy on the Medium, Easy, and Beginner levels.  This is annoying; and at present, it largely defeats the purpose of having Beginner and Easy levels in the game.  For more discussion on this subject, see the thread started by EmperorJarin, entitled: "The day that Easy became too hard".  (I should add, that I remain hopeful that the FE Devs will get this properly sorted out, in a later update.  But if you share this concern, please add your feedback to the "Easy" thread.  Thanks!)