参照 ("A"B"C") に対する ShellCheck 警告

単純なシェルスクリプトを作成していますが、スクリプトを確認するときhttps://www.shellcheck.net14行目でエラーが発生します。

Line 14:
  sysrc ifconfig_"${Bridge}"="addm ${NIC}"
                            ^-- SC2140: Word is of the form "A"B"C" (B indicated). Did you mean "ABC" or "A\"B\"C"?

https://github.com/koalaman/shellcheck/wiki/SC2140

実際に修正する方法がわからない

#!/bin/sh

Setup() {
  # Determine interface automatically
  NIC="$(ifconfig -l | awk '{print $1}')"
  # Enabling the Bridge
  Bridge="$(ifconfig bridge create)"
  # Next, add the local interface as member of the bridge.
  # for the bridge to forward packets,
  # all member interfaces and the bridge need to be up:
  ifconfig "${Bridge}" addm "${NIC}" up
  # /etc/rc.conf
  sysrc cloned_interfaces="${Bridge}"
  sysrc ifconfig_"${Bridge}"="addm ${NIC}"

  # Create bhyve startup script
  touch /usr/local/etc/rc.d/bhyve
  chmod +x /usr/local/etc/rc.d/bhyve
  cat << 'EOF' >> /usr/local/etc/rc.d/bhyve
#!/bin/sh
# PROVIDE: bhyve
# REQUIRE: DAEMON
# KEYWORD: shutdown
. /etc/rc.subr
name=bhyve
start_cmd="${name}"_start
bhyve_start() {
}
load_rc_config "${name}"
run_rc_command "$1"
EOF
  sysrc bhyve_enable="YES"
}