Thanks, ntm. Must have just not been patient enough for the new feed.
I’m having issues with one of my feeds.
feed://emergentradio.com/feed/thetoolbar/ works fine.
feed://emergentradio.com/feed/theundercast/ is broken. I just published the first show in this category today, and the settings are exactly the same for both feeds, except for the category.
Resolution: http://ww.wp.xz.cn/support/topic/problem-with-user-list?replies=2#post-2211187
I updated all three files and just tested the individual email and it worked.
I made this change in the code in these two files, as well as in the email-users.php file and it fixed the individual email issue.