I've met a few of these but the most recent instance was two characters discussing buying a third character a drink when they all got home, on the first reading this is a simple moment of comradery and thanks giving for what they owe that person. When reading the series again this moment takes on a more poignant note, the character dies in a later book, and knowing they never get their bottle of booze makes the moment very different.
I'm wondering if there's a specific name for these moments that are simple the first time and sad when reread because of the ultimate fate of the characters involved?