Qual é o problema com 'PidFile' na seção 'Service' (Unknown lvalue 'PidFile' na seção 'Service')?

Eu tenho um arquivo de serviço systemd usando instâncias que funciona bem para starte status, mas depois stopde um subsequente statusexibe estas mensagens de erro:

Runtime directory is not valid, ignoring assignment: /var/run/iotwatch/%i
Unknown lvalue 'PidFile' in section 'Service'

Aqui estão os detalhes: Primeiro, o arquivo de serviço /usr/lib/systemd/system/[email protected]:

[Unit]
Description=iotwatch I/O performance monitor instance %I
Documentation=man:iotwatch(1)
PartOf=iotwatch.target
#Requisite=
After=nss-user-lookup.target time-sync.target paths.target
#Before=

[Service]
Type=forking
Environment="IOTWATCH_INSTANCE=%i"
RuntimeDirectory=/var/run/iotwatch/%i
WorkingDirectory=/var/run/iotwatch/%i
ExecStart=/usr/lib/iotwatch/iotwatch-service-wrapper %i start
#ExecReload=/usr/...
ExecStop=/usr/lib/iotwatch/iotwatch-service-wrapper %i stop
#SyslogIdentifier=%p-%i
TimeoutStopSec=30
PidFile=/var/run/iotwatch/iotwatch-%i.pid
Restart=always
RestartPreventExitStatus=5 6
StartLimitBurst=1

[Install]
WantedBy=multi-user.target

Em seguida, o status após o início:

h02:~ # systemctl start iotwatch@VAR -l
h02:~ # systemctl status iotwatch@VAR -l
● [email protected] - iotwatch I/O performance monitor instance VAR
   Loaded: loaded (/usr/lib/systemd/system/[email protected]; disabled; vendor preset: disabled)
   Active: active (running) since Thu 2019-04-25 11:40:47 CEST; 6s ago
     Docs: man:iotwatch(1)
  Process: 12907 ExecStart=/usr/lib/iotwatch/iotwatch-service-wrapper %i start (code=exited, status=0/SUCCESS)
 Main PID: 12920 (iotwatch-VAR)
    Tasks: 4 (limit: 512)
   CGroup: /system.slice/system-iotwatch.slice/[email protected]
           └─12920 ./iotwatch-VAR -l /var/log/iotwatch/VAR/iotwatch-VAR.log -m I -p /var/run/iotwatch/VAR/iotwatch-VAR.pid -d1 -a0.00 -b512 -i4 -sD -t0.5 -TX=0.25:0.50,A=0.025:0.05 -OR -OS:T=F75,S:M=O52,N:3.29/60,Q:C=120,P:nagios.nagios=0664 /dev/sys/var

Apr 25 11:40:47 h02 systemd[1]: Starting iotwatch I/O performance monitor instance VAR...
Apr 25 11:40:47 h02 iotwatch-service-wrapper[12907]: Starting iotwatch VAR
Apr 25 11:40:47 h02 systemd[1]: Started iotwatch I/O performance monitor instance VAR.
h02:~ # ll /var/run/iotwatch/VAR/iotwatch-VAR.pid
-rw-r--r-- 1 root root 6 Apr 25 11:40 /var/run/iotwatch/VAR/iotwatch-VAR.pid

E, finalmente, o status após a parada:

h02:~ # systemctl stop iotwatch@VAR -l
h02:~ # systemctl status iotwatch@VAR -l
● [email protected] - iotwatch I/O performance monitor instance VAR
   Loaded: loaded (/usr/lib/systemd/system/[email protected]; disabled; vendor preset: disabled)
   Active: inactive (dead)
     Docs: man:iotwatch(1)

Apr 25 11:40:47 h02 systemd[1]: Started iotwatch I/O performance monitor instance VAR.
Apr 25 11:41:24 h02 systemd[1]: Stopping iotwatch I/O performance monitor instance VAR...
Apr 25 11:41:24 h02 iotwatch-service-wrapper[12962]: Stopping iotwatch VAR
Apr 25 11:41:27 h02 systemd[1]: Stopped iotwatch I/O performance monitor instance VAR.
Apr 25 11:41:27 h02 systemd[1]: [/usr/lib/systemd/system/[email protected]:12] Runtime directory is not valid, ignoring assignment: /var/run/iotwatch/%i
Apr 25 11:41:27 h02 systemd[1]: [/usr/lib/systemd/system/[email protected]:19] Unknown lvalue 'PidFile' in section 'Service'
Apr 25 11:41:27 h02 systemd[1]: [/usr/lib/systemd/system/[email protected]:12] Runtime directory is not valid, ignoring assignment: /var/run/iotwatch/%i
Apr 25 11:41:27 h02 systemd[1]: [/usr/lib/systemd/system/[email protected]:19] Unknown lvalue 'PidFile' in section 'Service'
Apr 25 11:41:32 h02 systemd[1]: [/usr/lib/systemd/system/[email protected]:12] Runtime directory is not valid, ignoring assignment: /var/run/iotwatch/%i
Apr 25 11:41:32 h02 systemd[1]: [/usr/lib/systemd/system/[email protected]:19] Unknown lvalue 'PidFile' in section 'Service'

Como posso corrigir o arquivo de serviço para evitar essas mensagens?