Frustrated as well, created simple script to remove /tmp/crl.pem, recreate it by get-api-crl and forcing updater.sh 
and set it in cron 
(option “-q”). No more troubles Case you are interested:
# mend corrupted/missing /tmp/crl.pem file
# causing updater.sh failing
QUIET=NO
for i
do
case $i in
-q) QUIET=YES
;;
esac
done
if [ -f /tmp/crl.pem ]
then rm /tmp/crl.pem
MSG="/tmp/crl.pem removed & recreated"
else MSG="/tmp/crl.pem created"
fi
if [ “$QUIET” == “YES” ]
then get-api-crl 2>/dev/null
echo -e “Subject: /tmp/crl.pem\n\n$MSG” | msmtp root
updater.sh 2>/dev/null
else echo "$MSG"
get-api-crl
updater.sh
fi
You may want to change mail via msmtp (should be configured!) by /usr/bin/create_notification -s {news|error} $MSG $MSG
(forgive improper formatting, have no patience to play with it in comments