If this is a bug in systemd it belongs at systemd no matter which version it is. If systemd doesn't want to do support that is their choice but distros aren't the right place to post systemd bugs. It only belongs there if it is either a bug in the distro itself or a support request for distro specific problems.
If you go filing bugs against old versions of systemd in the github issues, you're likely just going to receive a canned reply along the same lines of what I've already said.
You may not like it, I'm just playing messenger here, to try save some bother on both sides of this subject. Use the mailing list for support questions, or contact your distro vendor for support.
