mergerfs.dup doesn't respect branch type NC

[magma1447]

I am trying to migrate files away from one of the sources behind a mergerfs. The current branches setup looks like this.
/mnt/md0=NC:/mnt/md1=RW:/mnt/md2=RW:/mnt/md3=RW

I have a cronjob that looks like this:
/usr/local/bin/mergerfs.dup --count=2 --prune --execute /data/foo

This cronjob keeps duplicating files from /data/foo into my md0. That can't be intentional?

[trapexit]

It's "intentional" in that the tool does not consider any settings of the pool (outside the branch list that is). It was written before those options even existed if I remember correctly.