KMadCandy
giggling permanoob
when the AI signs a peace treaty, the -at war penalties go away instantly, which often changes the status of the relationship (annoyed -> cautious for example). the change in status is properly shown instantly. but in cases where that makes the person they were at war with no longer their worst enemy, the game does not recognize that they're not enemies until the following turn.
note: the AI's worst enemy is whoever they're annoyed or furious with that they hate the most. if they are cautious or higher towards someone, they do not consider that person their worst enemy.
1. choose single player
2. load attached save
3. note Shaka's attitude to Cyrus. Annoyed, -7
4. bribe Shaka compass to sign peace with Cyrus. that instantly changes Shaka's attitude to Cyrus to Pleased, +1. therefore Cyrus cannot be Shaka's worst enemy.
5. note Shaka's attitude towards you. +1. now save the game, to make the next steps easier 
6. before hitting enter, trade with Cyrus. compass for gold works.
7. note Shaka's attitude towards you. you earned negative modifiers for trading with his worst enemy, but the person you traded with is someone he is pleased with, and can't be his worst enemy!
8. just to be thorough, hit enter and verify that the -worst enemy penalty doesn't go away.
showing that it's a bug:
9. load the save you made at step 5, or repeat steps 1-4.
10. this time, hit enter after Shaka likes Cyrus but before you trade with Cyrus, to let the internal "worst enemy" system catch up to the display that you see.
11. note that Shaka's attitude toward everyone is still the same, including Cyrus. so his worst enemy, if he had one, would be the same person that it was last turn.
12. make a tech trade with Cyrus now. doesn't matter what.
13. note Shaka's attitude towards you. +1 as it originally was, with no "worst enemy" penalty.
the AI's worst enemy isn't ever displayed on the screen, you just have to figure it out. my guess, for what it's worth, is that's the problem. because it's behind-the-scenes, it's only calculated between turns? in this game, the entire reason for bribing shaka to sign peace was to trade with cyrus without getting negative modifiers, so this bug had a major negative impact.
this game was played in 3.13 with Bhruic's unofficial patch. i also have a save (like this one, courtesy of Sisiutil) played with the previous BtS patch where this shows up. two AIs are calling the player their worst enemy even tho they're Cautious toward him, on the turn that they signed a peace treaty. the very next turn they are willing to trade with him and don't call him their worst enemy. so this is not new to 3.13, and i don't even know whether it's new to BtS.
note: the AI's worst enemy is whoever they're annoyed or furious with that they hate the most. if they are cautious or higher towards someone, they do not consider that person their worst enemy.
1. choose single player
2. load attached save
3. note Shaka's attitude to Cyrus. Annoyed, -7
Spoiler :

Spoiler :


6. before hitting enter, trade with Cyrus. compass for gold works.
7. note Shaka's attitude towards you. you earned negative modifiers for trading with his worst enemy, but the person you traded with is someone he is pleased with, and can't be his worst enemy!
Spoiler :

showing that it's a bug:
9. load the save you made at step 5, or repeat steps 1-4.
10. this time, hit enter after Shaka likes Cyrus but before you trade with Cyrus, to let the internal "worst enemy" system catch up to the display that you see.
11. note that Shaka's attitude toward everyone is still the same, including Cyrus. so his worst enemy, if he had one, would be the same person that it was last turn.
12. make a tech trade with Cyrus now. doesn't matter what.
13. note Shaka's attitude towards you. +1 as it originally was, with no "worst enemy" penalty.
the AI's worst enemy isn't ever displayed on the screen, you just have to figure it out. my guess, for what it's worth, is that's the problem. because it's behind-the-scenes, it's only calculated between turns? in this game, the entire reason for bribing shaka to sign peace was to trade with cyrus without getting negative modifiers, so this bug had a major negative impact.

this game was played in 3.13 with Bhruic's unofficial patch. i also have a save (like this one, courtesy of Sisiutil) played with the previous BtS patch where this shows up. two AIs are calling the player their worst enemy even tho they're Cautious toward him, on the turn that they signed a peace treaty. the very next turn they are willing to trade with him and don't call him their worst enemy. so this is not new to 3.13, and i don't even know whether it's new to BtS.