Factions at war, but not attacking

[Big_H]

I'm a vassal of Swadia, they have been at war with Khergit Khanate for most of the game. In the beginning, before I had an army worth mentioning, the King and Lords were down fighting and looting constantly. Shortly after I joined Swardia, the Rhodoks declared war on the Khergit too. As soon as that happened all the Swardia armies returned home. The King has been sitting in Praven for over a month, and all the Lords are out patrolling around their own lands.
The Rhodoks, with my help, pressed the war on the Khergit taking over half their lands. All the while the armies of Swadia didn't leave their lands. The last time the King left Praven was when war was declared with Vaegirs. He made one trip into their lands, was defeated, and has spent the rest of the time sitting in Praven.
So now all of a sudden, the Nords make a push south and also declare war on the Khergit. As soon as that happens the Rhodoks, who up till now had been decimating the Khergit, pull all their troops back to their homeland.
All of these factions are still at war with the Khergit, but the Nords are the only ones who have armies down there fighting.

So it seems like as soon as a new faction declares war, the faction that was already fighting withdraws, though they are still labeled as "at war".
Has anyone else run into this before? Is it a known bug or anything? And most importantly, does anyone know how to fix it so we can finally eliminate the Khergit? It's been at "we've got 17 armies while they have 2. Overall, we are about to win this war." for far too long.

Thanks

 

[Shishou]

I wouldn't be surprised if the strategic AI is more aggressive when it has only one enemy than multiple enemies, so your observations make sense, though I can't confirm that this is always the case.  I do know that the AI can be maddeningly passive even against one enemy, so if your NPC lords have already snagged some castles, count yourself lucky.  And you haven't seen real passivity out of the AI until you've played Prophesy of Pendor and joined the Empire.

Fixing it: operationally, the easiest way would be for you to grab a double handful of Swadian Knights and just go beat the snot out of the Khergits yourself.  The Khanate does pretty poorly in close quarters infantry combat, so once you get Knights up the ladder in a castle and onto the ramparts, you should be able to mow through the defenders.  If you need more troops to avoid getting swarmed, hope you get elected marshal or if you have a lord who REALLY likes you (relations of 25+) you could try commanding him to follow you.  Generally, faction AIs don't kill off other faction AIs - they're like gentlemen who fence a bit and occasionally poke each other a few times, while the player's more like the psycho with the chainsaw. 

I have no ideas about monkeying around with the code.

Oh, and the "We have X armies and they have Y armies" report means very little; as noted above, the AI won't reliably take advantage of any strategic advantage that it may have.

 

[Northcott]

From what I've seen, army sizes play into it. I'm used to the Rhodoks and Northmen running home to lick their wounds until they've got nice, big, fat armies ready to come charging down on Vaegir lands again. Then they'll mass in a group of seven or eight lords, and bring down a massive army on the worst-defended castle they can find... even if it's well behind the front lines.