Did a bit of digging...
The cause of the problem is charevent 7315 in the courtier_events, and it certainly appears to be a bug. This is definitely present in the latest beta, and the event that CerberusIV is describing is definitely charevent 7315, detailed below:
# Is chancellor and not in chancellor position
character_event = {
id = 7315
picture = "event_default"
trigger = {
condition = { type = ai }
condition = { type = age value = 16 }
condition = { type = not value = { type = marshal } }
condition = { type = not value = { type = steward } }
condition = { type = not value = { type = chancellor } }
condition = { type = not value = { type = spymaster } }
condition = { type = not value = { type = ruler } }
condition = { type = diplomacy value = 1 }
condition = { type = or
condition = { type = not value = { type = chancellor_csc condition = { type = chancellor } } }
condition = { type = and
condition = { type = diplomacy value = 7 }
condition = { type = not value = { type = diplomacy value = 8 } }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 7 } } }
}
condition = { type = and
condition = { type = diplomacy value = 8 }
condition = { type = not value = { type = diplomacy value = 9 } }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 8 } } }
}
condition = { type = and
condition = { type = diplomacy value = 9 }
condition = { type = not value = { type = diplomacy value = 10 } }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 9 } } }
}
condition = { type = and
condition = { type = diplomacy value = 10 }
condition = { type = not value = { type = diplomacy value = 11 } }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 10 } } }
}
condition = { type = and
condition = { type = diplomacy value = 11 }
condition = { type = not value = { type = diplomacy value = 12 } }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 11 } } }
}
condition = { type = and
condition = { type = diplomacy value = 12 }
condition = { type = not value = { type = diplomacy value = 13 } }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 12 } } }
}
condition = { type = and
condition = { type = diplomacy value = 13 }
condition = { type = not value = { type = diplomacy value = 14 } }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 13 } } }
}
condition = { type = and
condition = { type = diplomacy value = 14 }
condition = { type = not value = { type = diplomacy value = 15 } }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 14 } } }
}
condition = { type = and
condition = { type = diplomacy value = 15 }
condition = { type = not value = { type = chancellor_csc condition = { type = diplomacy value = 15 } } }
}
}
}
mean_time_to_happen = {
months = 60
}
immidiate = {
effect = { type = chancellor }
}
}
According to the extra_text, this event should have three possible options:
a) I must think about this before deciding
b) Indeed! And so you shall be!
c) Rebuff such an outrageous demand
However, as you can see, no action options have been written in. The event automatically assigns the targeted character to the chancellor position and then gives the default response of whatever is written as action a). Ironically, this is actually the exact opposite of the WAD effect of choosing action a).
Shouldn't take too much to fix. Actually, all of the # (x position) generic events # in the courtier_events are plagued with exactly the same bug, so it might be worth going over all of them before the patch is finalised.
Cerberus, as a quick fix for that particular piece of insanity, goto Crusader Kings/db/events/courtier_events.txt and search or scroll for the generic events. Put a # before the immidiate = lines, so that they read:
# immidiate = {
# effect = { type = chancellor }
# }
That way, if and when the event does trigger, it will have no effect on gameplay and will stop turning your bishop into a chancellor.