Comcast has changed the way they do spam filtering as described here:
If they decide emails from the club are spam, their default is to delete them rather than deliver them to your spam folder. We can't see that on the club end as Comcast reports back to us that they've delivered the message. For some reason, their filters have gotten very aggressive with our emails over the last few weeks.
The page linked above describes how to change that behavior so that messages Comcast's filters determine are spam are delivered to your spam folder instead. Please follow the instructions there to enable "Save a copy of emails marked as spam." You'll need to watch your spam folder, and, when they flag a club email as spam, please click the "not spam" button to train their filters.
Note that this issue impacts Comcast email users (@comcast.net email addresses). It does not impact Comcast internet users who use other email services (GMail, Yahoo, Outlook, etc.).