I saw this movie last August at a showing at the Computer History Museum and one thing really confused me. The documentary includes a dramatized 1980s interview

I saw this movie last August at a showing at the Computer History Museum and one thing really confused me. The documentary includes a dramatized 1980s interview between a fictional interviewer ("Michelle", played by Kaliswa Brewster, who I think represents a combination of the interviewers Anthony Liversidge and John Horgan who met Shannon at his home in the late 1980s) and actors portraying Claude and Betty Shannon. I'm totally on board with this way of re-enacting or dramatizing an interview when everybody shown is an actor. But later we see an interview with Shannon's real first wife, Norma (Levor) Barzman, who went on to become a well-known Hollywood screenwriter (and Communist!), and who amazingly was something like 97 years old at the time of the interview. Eventually (around 27 minutes in to the movie) we hear the voice of the same fictional interviewer offscreen. The interviewer shares a revelation with Norma: that Claude Shannon quit his fellowship at the Institute for Advanced Study after only two months to go work for the war effort, apparently without telling her, and around the time their marriage went sour. This comes across as a big surprise to Norma (28 minutes in). The presence of the fictional interviewer interviewing the real Norma (who also doesn't look 97, but pretty sure that's really her) confused me -- are we meant to take literally that Norma Barzman never knew that Claude Shannon had quit IAS and gone to work for the war effort until 75 years later when Kaliswa Brewster, playing a fictional character, told her in the process of filming a semi-dramatized documentary about her first husband? Norma was interviewed for the book (which also includes this information) in 2014 -- did she really not know? Was this the first take of the interview or is Norma also "acting" here...? Why use the same "interviewer" in both a fictionalized interview with other actors and a real one? Was Brewster actually there interviewing her, or is her voice just dubbed in later so the audience doesn't have to hear the real documentarian's voice? Or am I just mistaken and the offscreen voice is somebody else? It really sounds like her!