Just had a conversation with a friend of mine and I can't believe I didn't catch this earlier, but I now actually think there's a reason they did that...
Louise was basically unfazed by the news/crowd of students around the TV in the lobby area because of subconscious, "future deja vu." Later, after she masters the alien's language and it "rewires" her brain, she can then obviously understand the past, present, and future simultaneously. And the present manifests itself as the most vivid parts of the "dream." Like when she's actually working to decipher the aliens, but it's all still a "dream" of sorts nonetheless. Hence not relating to the students, going home and taking a nap, being the only person to show back up to campus seemingly unfazed, etc. Yes, the first time around all that could be interpreted as either a teacher simply being a teacher, or still being depressed over the death of her daughter (when we thought those were flashbacks), but looking back, there's no way a movie like this doesn't make that decision on purpose.
Thoughts?