In Historical Battle Honfoglalas the Bulgarians (Green) change their diplomacy with you to enemy when you get near them. Have not taken up the Byzantine (Blue) offer and have not received 2000 gold. It makes the mission intolerably difficult. This hasn’t happened every time but has happened consistently after the following steps:
Immediately attack yellow, putting all villagers on deer, and destroy their three town centres and kill all yellow villagers. Create only light cav throughout. Yellow resigns.
Send villagers to stone. Attack orange, destroy TC and kill villagers and attack some orange military in the west. (Unclear what Orange’s trigger for resigning is but they usually resign soon after this).
Around here red send their first lot of troops to attack.
Send villagers to cliffs in the east of the map (the southernmost ones nearest green). Green’s units do not attack when you go past them until…
Your villagers near green’s easternmost fortifications. When in sight of the two towers outside the small base with a Krepost in it, green (Bulgarians) change diplomacy to enemy and kill my villagers .
With red and green attacking this makes the scenario almost impossible (to me). I resign.
I didn’t think a screenshot would help but if it does I can recreate and send one!