In combat, a xeno will be forced to switch to a new tether (such as one behind you) so as to flank or disperse so they aren't so grouped up, etc." Thanks to how the engine parsed this typo, it never caused any crashes; instead, the engine ignored the unfamiliar term.
This 2017 post came shortly after the release of the group's final "Game Over, Man!" patch, which, among many other fixes, overwrites this INI file with the typo's correction.
Gearbox has not updated the game's PC version since July 2013, and the typo is still there.
In both missions, xenomorph AI improved dramatically once the typo was corrected, with monsters immediately taking advantage of elevated attack positions, hiding points, and multi-monster flanks.