Also in favour. Especially when it's something like the fight for the expedition base on dominating and you've cleared pretty much every enemy and then miss with a 90% chance cryokinesis and one shard happens to hit your Naga Protector.
Also pretty sure some AI just don't care if they hit an ally with an AOE. That same Naga Protector, for example, straight up one-shot me because I was a diagonal square away from a cultist. They could have fired at any of the other 5 that had just spawned but instead just obliterated me without thought. (They didn't miss because it landed right on the guy they were aiming at, so I was predictably in it's blast radius). Also heard that if a tchortist hits you with an incendiary bolt during the faceless fight then it can turn them hostile too, and that's them hitting you... No verification on that one though.
It does make it very difficult to use some skills though. Especially as a psi user. Every fireball or iceball is rolling the 10 sided dice. Electrokinesis is almost definitely out. Electrostatic imprint is a little more reliable but still risky. An ally might make it impossible to move your kinetic proxy into position. Pyrokinetic stream is a risk if there's anyone one or two tiles away from the stream. Thermodynamic destabilisation is pretty much a nightmare if you've got any melee allies.
Not actually sure about exothermic aura since it's green in the abilities menu. Typically red abilities will make allies hostile and green don't bother allies. Not sure if that's because it's technically a buff and whether the actual flames would cause hostility or if the whole ability is considered fine.
Also it's pretty annoying that aggroing any member of a faction will turn the rest of that faction hostile immediately. Really diminishes the usefulness of stealth and silent weapons. It's not even all that consistent. Like in the red army base, you're supposed to kill an officer and steal their uniform. Except the rest of the game you've been taught that if you kill someone of a faction they'll immediately turn hostile. If you do it with anyone else in the grey army base then again, they all turn hostile.
It's a stupid arbitrary rule that takes away from the game. If you want someone to be essential then have an unbreakable security camera pointed at them or something.