Output contains `Operation not permitted`

[code-noggin]

Some commands are getting Operation not permitted in their stderr.
I noticed this originally with the 1.11.3 release, but its still happening with the v1.13 release.

$ grc df -h
df: /run/user/1000/doc: Operation not permitted
Filesystem      Size  Used Avail Use% Mounted on
udev             16G     0   16G   0% /dev
tmpfs           3.2G  2.1M  3.2G   1% /run
/dev/nvme0n1p4  368G   13G  337G   4% /
tmpfs            16G  162M   16G   2% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
/dev/nvme0n1p1  523M   18M  506M   4% /boot/efi
tmpfs           3.2G  200K  3.2G   1% /run/user/1000

$ grc df 1>/dev/null
df: /run/user/1000/doc: Operation not permitted

$ grc -v
Generic Colouriser 1.13
grc [options] command [args]

$ grep PRETTY_NAME /etc/os-release
PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"