FYI, I ran a grep on my Application Support folder and found the following:
./Application Support/J River/Media Center 23/Settings/User Settings.ini:0="http://www.kqed.org/radio/listen/pledgefree/play/email.com/code/kqedpfs_fall_2017.m3u"
./Application Support/J River/Media Center 23/Settings/User Settings.ini:1="http://www.kqed.org/radio/listen/pledgefree/play/email.com/code/kqedpfs_fall_2017.m3u"
./Application Support/J River/Media Center 23/Settings/User Settings.ini:2="http://www.kqed.org/radio/listen/pledgefree/play/email.com/code/kqedpfs_fall_2017.m3u"
./Application Support/J River/Media Center 23/Settings/User Settings.ini:3="http://www.kqed.org/radio/listen/pledgefree/play/email.com/code/kqedpfs_fall_2017.m3u"
./Application Support/J River/Media Center 23/Settings/User Settings.ini:5="http://www.kqed.org/radio/listen/pledgefree/play/email.com/code/kqedpfs_spring_2017.m3u"
./Application Support/J River/Media Center 23/Settings/User Settings.ini:6="http://www.kqed.org/radio/listen/pledgefree/play/email.com/code/kqedpfs_fall_2017.m3u"
I deleted the offending lines and it's working. It would be nice if there was a way to do this on the front end.