file_check collector doesn't show dir_size for /var/log

I’m using the Files and directories collector and I have a job which looks like this:

  - name: directory_size_monitoring
    discovery_every: 30s
      collect_dir_size: yes
        - '/etc/pihole/'
        - '/var/log/'

All the charts work fine except for the Directory size one (filecheck.dir_size).
It shows the “/etc/pihole” directory fine but not “/var/log”.
When I run the collector in debug mode I can see that it’s not getting any dir_size value for that path (it gets it for all the other metrics for that path such as number of files etc).

BEGIN 'filecheck_directory_size_monitoring.dir_size'
SET '/etc/pihole/' = 449
SET '/var/log/' =

I have verified that the Netdata user has the required permissions to the files (the debug logging indicates no such error anyhow).

The only thing I can think of is that /var/log is on tempfs as I’m using log2ram.

The relevant line from df -h gives me:

log2ram         300M   74M  227M  25% /var/log

and mount gives me:

log2ram on /var/log type tmpfs (rw,nosuid,nodev,noexec,noatime,size=307200k,mode=755,inode64)

Agent version is: netdata v1.42.0-63-nightly