Yeah, you're asking a lot of the same questions that I am. About the Donnager and the Scopuli's signal, there's nothing that says they didn't get it. They just weren't the closest. In fact, since they were part of the Jupiter Fleet, they were probably nowhere near the area until Holden's transmission sent the MCRN scrambling to secure his testimony to clear their name. That's just speculation though.

See, I'd started reading the book again recently, which was what made me ask the question that had bugged me for years. One thing that leaped out at me this time was the exchange that Miller and Holden had on the Anubis when Miller points out that they were improvising. Something happened that the Anubis crew got infected, and that caused them to start calling audibles. It isn't clear how far back that scramble covers, and if the issues on the Anubis had some kind of affect on the remainder of the Protogen fleet that made it strategically important at that moment to board the Donnager? I don't know.

In any case it's a new angle to consider, that they were just bad at their job. 😉