plugins: sysutils/monit: filesystem statistics error -- cannot parse device '/dev/gpt/rootfs'

Hey,

my system log gets spammed by the following message since weeks or even month:

Sep 14 10:59:07 | monit[53265]: filesystem statistics error -- cannot parse device '/dev/gpt/rootfs'
Sep 14 10:57:07 | monit[53265]: filesystem statistics error -- cannot parse device '/dev/gpt/rootfs'
Sep 14 10:55:07 | monit[53265]: filesystem statistics error -- cannot parse device '/dev/gpt/rootfs'
Sep 14 10:53:07 | monit[53265]: filesystem statistics error -- cannot parse device '/dev/gpt/rootfs'
Sep 14 10:51:07 | monit[53265]: filesystem statistics error -- cannot parse device '/dev/gpt/rootfs'
Sep 14 10:49:07 | monit[53265]: filesystem statistics error -- cannot parse device '/dev/gpt/rootfs'
Sep 14 10:47:07 | monit[53265]: filesystem statistics error -- cannot parse device '/dev/gpt/rootfs'

On ui/monit/status/ everything looks fine:

Monit 5.23.0 uptime: 8d 2h 58m

System 'opnsense.example.com'
  status                       OK
  monitoring status            Monitored
  monitoring mode              active
  on reboot                    start
  load average                 [0.42] [0.34] [0.27]
  cpu                          1.9%us 1.6%sy
  memory usage                 628.3 MB [15.5%]
  swap usage                   0 B [0.0%]
  uptime                       8d 3h 0m
  boot time                    Wed, 06 Sep 2017 11:47:53
  data collected               Thu, 14 Sep 2017 14:47:15

Filesystem 'RootFs'
  status                       OK
  monitoring status            Monitored
  monitoring mode              active
  on reboot                    start
  filesystem type              ufs
  filesystem flags             soft updates, noatime, local, rootfs
  permission                   755
  uid                          0
  gid                          0
  block size                   4 kB
  space total                  13.5 GB (of which 8.0% is reserved for root user)
  space free for non superuser 11.2 GB [82.8%]
  space free total             12.2 GB [90.8%]
  inodes total                 1845886
  inodes free                  1809716 [98.0%]
  data collected               Thu, 14 Sep 2017 14:47:15

The file however is there:

~ # ls -l /dev/gpt/rootfs 
crw-r-----  1 root  operator  0x56 Sep  6 11:47 /dev/gpt/rootfs

Could this be a configuration import/export problem as in https://github.com/opnsense/plugins/issues/243?

OPNsense version strings:

OPNsense 17.7.2-amd64
FreeBSD 11.0-RELEASE-p12
LibreSSL 2.5.5