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Characters' mouths are acting really weird and not looking right. Sometimes they just hang slightly open with a "dur hur" kind of expression on their face. Was this intentional or is there some sort of shenanigans going on with my computer?
This question / problem has been solved by WeakSetimage
That is correct, nothing wrong with your system. Faces will never look natural in games and in this game the baseline is "hur dur". At least they have captured real expression movements on top of that.