Ok, 1.26, Extreme difficulty. Scavenger-type minor (NOT a farmer).
Turn 3 - Minor does not have a protector (Pic 1)
Turn 4 - Minor got a protector (Pic 2)
Turn 6 - Minor is annexed by Major (Pic 3). Save-loading does not help, it is annexed 100% of tries.
Minor borders: Major-protector, another Minor and non-aligned. So, Minor should not be annexed by protection mechanics, when attacked by another Major.
If I happen to grab a protector status on Turn 3, unification card shows 3d100+35 skill check (Pic 4). Tough guys, unwilling to cooperate, like it is expected. With a client state status (if the Major happened to obtain it on Turn 5, which I am not sure of) the difficulty would be 2d100+35
Finally, on Turn 6 the highest Charisma in game is 47, the highest oratory skill is 37 (known thanks to debug, and I am not sure if the Major in question has all that - there are 10 other Major Regimes, one can have char 47 guy (actually, I have him), another - oratory 37). So, the highest roll theoretically possible is 1d100+84. Agaist (2d100 or 3d100) + 35 + relation difference adjustment.
The question is - how much of an advantage does AI have in Minor Diplomacy? On extreme difficulty, is it intentionally designed that a Raider-type Minor can be annexed by AI Major on Turn 6, without any relation improvement steps?