Thanks @bonnietwin for the background info!!!
According to the post Log Summary - OpenVPN - No CRL Update - #4 by ummeegge by @ummeegge a workaround, until the Core Update, could be to change OPENSSLCONF in the updater script.
So as I am at the moment abroad on vacation and do not want to be worried, I edited /etc/fcron.daily/openvpn-crl-updater to
#OPENSSLCONF=“${OVPN}/openssl/ovpn.cnf”
OPENSSLCONF=“/usr/share/openvpn/ovpn.cnf”