Hello, our team tried to reproduce the issue but was unable to. I will update the team about your findings tho. Thank you for your time.
so I dont get it?
What did you try to replicate.
Did you start that save and just go around fighting lords with other clanleadparties in your army, to "hope" that one of them will not properly release the rescued lord(as in instead take them into their party like a unit).
Or did you track down the npc who have the lord who wasnt released as normal, in the other party?
The problem is that this issue happends "rare" but can happend among any lord and even king I had Raganavad of Sturgia have another sturgian lord in his army(that lord didnt get released until Raganavad was defeated in battle which is another option for it to happend).
Most of the time I fight big battles where some of the lords in my faction or other non-hostile with other parties in an army most of the time this issue dont happend.
But when it do, its really damageing for the overall gamebalance.
Since that lord thus cant form an army on their own(not to mention if its like in the case of the original poster, where the lord "takes control of the party" and it joins up in defense of other kingdomes etc, instead of joining your wareffort etc.)
In the save I provided back then in that thread I linked (the file is gone on my end though) I think it was called "Galden" cause that was the clanleader who wasnt released properly but was part of Raganavads party instead.
So basically what I'm trying to communicate is that hostile lord have prisoner who is either in your faction or another thats not hostile towards yours.
When the hostile lord is defeated, normally those lords being prisoner will be set free, however the issue is that instead those lords are picked up by other lords as a partymember instead.
The only way to "release" that lord from the party is by disbanding the party where he is in now(by defeat, disband)
This started when you introduced the new feature when you get that "thank you for setting me free" dialouge, instead of before it stated "was set free"(and you didnt get relations or anything).
So for some reason it seems that the ai dont always handle this properly and thus the lord instead goes into the party.