I am using the Steam version of the game with the CE edition mod, no other mods used
When in ground combat I have cleared a map of aliens outside the UFO and then prepared to assault the UFO (Scout) and kill the remaining aliens. I had one of my soldiers throw in a grenade, a flashbang or stun grenande, which started a fire inside the ship and killed most the aliens in the first larger room. I had to move my guys outside the ship as the fire kept spreading, including to the dry yellow grass field outside the ship.
When I went back into the ship I moved through the main room and tried to go through the narrow 2 square corridor to kill any remaining aliens in the forward smaller cockpit room but.. There is now a invisible alien blocking my way, which I can shoot and damage but do not seem to be able to kill. I am not sure if it is the only remaining alien or there is more in the cockpit which I can not access. I have also tried to stun the alien to no avail - it shows the damage numbers when it is attacked but does not die. Have attached a saved game (irongame mode) and screenshot.
Note that the invisible alien is highlighted with the cursor showing the red circle.
Steps to recreate: Unknown
-perhaps just start a fire in a ship with grenades
-if some of the aliens are killed by the fire out of line of sight it may create an invisible indestructable idle alien
Looks like I'll try killing it a couple more times and if that fails I will have to retreat and abort mission!
Aut.sav
Aut.sav