Turn 20 Question

[Absalom]

Over the years, I have seen and witnessed myself many reports of the aliens gaining full knowledge of the battlefield after turn 20, including but not limited to leaving the UFO on schedule.

While there are plenty of reports of this happening, there seems to be no actual information on what actually happens.  The crunch, if you will.  Do the aliens gain the Aggression stat?  Just knowledge of troop positions?  Does it affect the AI decision making at all?  Any feedback is appreciated. 

[Hobbes]

Over the years, I have seen and witnessed myself many reports of the aliens gaining full knowledge of the battlefield after turn 20, including but not limited to leaving the UFO on schedule.

While there are plenty of reports of this happening, there seems to be no actual information on what actually happens.  The crunch, if you will.  Do the aliens gain the Aggression stat?  Just knowledge of troop positions?  Does it affect the AI decision making at all?  Any feedback is appreciated.

After turn 20 the AI always know the location of all your units all the time. Doesn't affect aggression, it's more related to the intelligence stat (the number of turns that an alien remembers an XCOM unit's position).

The effects it has on the battlefield depend on the number of aliens left by turn 20. For the most times it results on the remaining aliens moving towards your troops but in UFOs the higher rank aliens usually still stick to their positions on the bridge. But I've also seen the AI perform mass attacks from several directions at the same time if there's still a lot of them around.

[Warboy1982]

one effect it has on the ai is to make them prefer attack actions over patrol, ambush or escape, where possible.

this is by no means absolute, it's merely an increased chance of them choosing that kind of action. what an "attack" action actually MEANS is also highly subjective and based on situational factors.