My long recording shows up as several rows, "part 1 of 6", "part 2 of 6" and so on. Why?

Recordings longer than about three and three quarter hours are stored as parts of up to three hours each, so that every part gets its own complete summary, key points and chapters and nothing is cut off. The file is transcribed once; the parts are only how the transcript is filed. Each part is its own Codex entry, named "Title (part 2 of 6)", with time stamps that still count from the start of the whole file. When you write a book from them, tick all the parts.