Random Guard orientation after movement is killing me

[Mathis]

I would say 50% of my deaths in this game (which I've already put 40 awesome hours in to) are due solely to the Hunting Guards turning 90 or 180 degrees after walking to and checking a destination. I'll have my agents hidden from them walking by, but then they'll randomly turn and spot/kill me. I think they should remain facing whatever direction they were when walking until next turn, otherwise trying to escape a 4+ tracker is more about luck than strategy.

[ildarz]

It's not random at all, at least in my knowledge. When you see guard in hunting mode, you can spent action point and predict his movement. His path will end with arrow pointing in the direction which guard will be facing in the end of his move. But when hunting guard reach suspicious spot, it will turn 90 degrees left and right, effectively extending his cone of sight to 270 degrees. Just plan your moves accordingly.

[TheUglyStick]

It's not random. After they investigate they turn around in the direction they came from to return to their patrol or post. 

[KajitiSouls]

If a guard runs out of AP on a square where it will turn next move, it will end its turn facing in the direction it intends to move next.  If there's a door in the way, it will open the door as well.  It is a bit mysterious at first, but you'll be able to anticipate their line of sight when you've seen it enough times.

 

TheUglyStick already covered what happens when a non-reinforcement guard investigates an area.

 

But when hunting guard reach suspicious spot, it will turn 90 degrees left and right, effectively extending his cone of sight to 270 degrees.

 

It's actually 180 degrees for a guard with the normal line of sight.