Cannot Add Dependency Service.R to multi-user.target, Ignoring: Invalid Argument

The Problem

Multiple systemd services has been failing to initialize due to Cannot add dependency issues:

Hostname systemd: Cannot add dependency dmraid-activation.service.R to sysinit.target, ignoring: Invalid argument
Hostname systemd: Cannot add dependency iscsi.service.R to sysinit.target, ignoring: Invalid argument
Hostname systemd: Cannot add dependency multipathd.service.R to sysinit.target, ignoring: Invalid argument
Hostname systemd: Cannot add dependency lvm2-monitor.service.R to sysinit.target, ignoring: Invalidargument
Hostname systemd: Cannot add dependency lvm2-lvmetad.socket.R to sysinit.target, ignoring: Invalid argument
Hostname systemd: Cannot add dependency lvm2-lvmpolld.socket.R to sysinit.target, ignoring: Invalidargument
Hostname systemd: Cannot add dependency microcode.service.R to basic.target, ignoring: Invalid argument

The Solution

Configuration files under /etc/systemd and the default.target in /etc/systemd/system has been appended .R at the end of its file name:

# cat /etc/systemd
bootchart.conf
bootchart.conf.R
coredump.conf
coredump.conf.R
journald.conf
journald.conf.R
logind.conf
logind.conf.R
system
system.conf
system.conf.R
user.conf
user.conf.R

# cat /etc/systemd/systemd
default.target -> ../../../usr/lib/systemd/system/multi-user.target
default.target.R -> ../../../lib/systemd/system/multi-user.target

Removing all of the configuration files that has .R on its name in /etc/systemd and /etc/systemd/system fixed the issue and was able to start the server properly.