It turns out that my specific problem was related to my email program. If you're not receiving email notifications for your Saved Searches and you use the Spectrum/Roadrunner email program, check your list of Blocked Senders. It is very easy to accidentally block more senders than you intend, because the boxes that you check to target a specific email sender are so small that you may not notice that other boxes are still checked from previous activity. Thus, you think you're only blocking the address of one spammer, but there's also other addresses that are still check-marked and those end up getting inadvertently blocked. Also, I've noticed that the Spectrum/Roadrunner email program will refresh while you are using it and sometimes check marks reappear in boxes that you've just removed.
