It has been a long five years since Aliens: Colonial Marines launched as a hot mess. Being critically panned by gamers and critics alike. One of the reasons behind the negative reception was the game's poor AI. The Xenomorphs had a tendency to run straight into gunfire. Or worse yet, would stand around or group up making them easy targets. Suffice to say the Xenomorphs were far from scary. A typographical error has been discovered as the reason behind some of those issues.

As noted on the ResetERA forums, a post by jamesdickinson963 on the ACM Overhaul ModDB page traced the problem to a spelling error in a single line of code within the game's ini file. The code shown below has "teather" instead of the proper "tether". This simple mistake in theory, results in the "zone tether" failing to load the AI parameters attached to the broken bit of code.

Original Code: ClassRemapping=PecanGame.PecanSeqAct_AttachXenoToTether -> PecanGame.PecanSeqAct_AttachPawnToTeather
Fixed Code: ClassRemapping=PecanGame.PecanSeqAct_AttachXenoToTether -> PecanGame.PecanSeqAct_AttachPawnToTether

Once the spelling mistake has been fixed it does seem to improve the game's AI, as corroborated by PCGamer's short video clips. In terms of improvements, the Xenomorphs tend to behave in a more aggressive manner, taking less time to attack the player. They also flank, leap and chase more often. Moments where the AI feels lost or confused still happen but the frequency is reduced.

If you have Aliens: Colonial Marines installed give the fix a try and let us know if you see a difference.
To change the code go to: My Documents\My Games\Aliens Colonial Marines\PecanGame\Config\PecanEngine.ini