This code is used to run the registration loop:

            set -xe;
            sleep \$(( \$RANDOM % 60 ));
            rpm --quiet -q katello-host-tools || yum -y install katello-host-tools;
            rpm --quiet -q zsh && rpm -e zsh;
            curl -X DELETE -k -s -u '{{ sat_user }}:{{ sat_pass }}' https://{{ satellite }}/api/v2/hosts/\$( hostname ) || true;
            subscription-manager status || true;
            for i in \$( seq {{ contreg_iter }} ); do
                subscription-manager unregister || true;
                subscription-manager status || true;
                if ! subscription-manager register --activationkey {{ content_activationkey }} --org {{ sat_orglabel }}; then
                    rc=\$?;
                    [ \"\$rc\" -ne 2 ] && echo \"ERROR: Registration failed with \$rc\" >&2;
                fi
                subscription-manager status | grep 'Overall Status: \(Current\|Invalid\)';
                subscription-manager refresh;
                yum -y install zsh;
                yum -y remove zsh;
            done &> {{ contreg_log }};
            tail {{ contreg_log }}"

What is important for this bug is the curl command.

Error happened sometime close to 2019-10-03T09:30:03.781Z

Hi,
I am seeing similar error for my systems kickstart (about 50 PCs).  If the system failed to register to the satellite (first step in my kickstart's postscript), the rest of the postscripts will failed and I got systems that not properly provision.
Is there any workaround for it?

Thank you for your interest in Satellite 6. We have evaluated this request, and while we recognize that it is a valid request, we do not expect this to be implemented in the product in the foreseeable future. This is due to other priorities for the product, and not a reflection on the request itself. We are therefore closing this out as WONTFIX. If you have any concerns about this feel free to contact your Red Hat Account Team. Thank you.