A+ombomb
Actuary
I am not entirely sure how to reproduce this bug....but I notice that if you slave excessively in a city, eventually the unhappiness will go completely wrong. For instance, I have seen several times where a city with size 6 and no unhappiness, slaved down 2 pops to 4, would suddenly be unhappy with 2 unhappiness. Since the act of slavery only induces 1 unhappy face, it would seem impossible to create any net unhappiness in a city 2 sizes smaller from the act, let alone 2 unhappiness. If anyone has more details on how to reproduce the bug they would be welcome, but for now I will try to dig up a game save.