Duplicate values for container_fs_usage_bytes in prometheus

[D3SL]

I'm not sure if I've misconfigured something at my end or this is a bug. container_fs_usage_bytes reports many duplicate entries, leading to the sum being much higher than it should be.

There's two sets of duplicates. The first is container_fs_usage_bytes{device="/dev/mapper/cl-root", id="/", instance="cadvisor:8080", job="cadvisor"} and then many variants of device="overlay_0-<number>", the other set are an entry for device="/x/y/z" paired with variants of device="/var/lib/docker/overlay2/<string>/merged/x/y/z".