I haven't noticed any missed notification e-mails myself... perhaps PM a Mod and see what they have to say. And then if you get a reply back from them without receiving a notification, you'll definitely know something is up! 😉😀
Nope, I run my own mail server and there's no filtering installed. Checking the mail queue (where sometimes errant messages sit and spin until the server figures out where they go) reveals nothing waiting for delivery.
I missed one this morning too. It seems to be isolated to MacRumors, as my vBul notifiers from howardforums.com work fine.