I wonder if these mischaracterizations indicate that other kinds of knowledge transfer are going on, like paper 2's advisor explained paper 1 from memory to their student (instead of them reading the paper from scratch) & that explanation isn't quite the same as what I get from a straight reading of paper 1
@omar Yeah, I think "other kinds of knowledge transfer are going on" is the right instinct. I'm always amazed by people who are able to absorb research merely by reading papers. There's tons of informal knowledge transfer that goes on in academia.
But also, while it's common for citations to misinterpret a paper (as anyone who's ever had their stuff cited knows), it's possible that the authors of paper 2 were somehow clued in about paper 1 in a way that wouldn't be obvious from reading paper 1.