The speaker says that about two years earlier his team used GPT-4 Turbo rather than GPT-3.5 because GPT-3.5 could not identify errors in the outputs.

“just possible when we are running the experiment otherwise it looks way we have seen situation previously where we were using probably gpt-4 turbo or something or even gpt-3.5 long back i'm talking like two years back um and we had to use gpt-4 turbo at the time because with the 3.5 it was something else entirely because it can't find errors”