When updating Jenkins via yum/dnf, the package overwrites the systemd config file located under /usr/lib/systemd/system/jenkins.service. Configurations (i.e. HTTPS-Setup) will be overwritten on every update. A standard package update procedure on RHEL is not intended to update configuration files such as the systemd service file, unless there are neccessary changes in said files.
To stop this behaviour, including a diff-check on these files would be great.
Administrators should use the override mechanism provided by systemd rather than modifying system provided files directly. The Jenkins documentation includes instructions in "Managing systemd services" that describe the technique for all supported Linux distributions using systemd.
The Red Hat Enterprise Linux 8 documentation says: