I have the exact same issue as everyone else. We dont have a control panel option for Antialiasing on Macs. Its in the game, but changing that doesnt change the subtitles.
I'm pretty sure this is a bug with Walking Dead. Hint: I've worked at NVIDIA for 12 years and seen these types of bugs before.
PM me if you need a Mac SW engineering contact at NVIDIA if you think its a driver bug.