Preseeding late command not running

Question

I got into preseeding today. Pretty easy and powerful but I still got this late_command at the very end of my preseed.cfg file I can't get working. None of these are being run when deploying my server. Any idea why ..? Can't see anything relevant in the logs.

d-i preseed/late_command string \
    mkdir -p /target/home/username/.ssh; \
    cat "ssh-rsa AAAAB3[...]" >> /target/home/username/.ssh/authorized-keys; \
    sed -i "s/^#include/include/g" /target/etc/sudoers; \
    in-target groupadd admin; \
    echo "%admin  ALL=(ALL:ALL) NOPASSWD:ALL" > /target/etc/sudoers.d/admin; \
    chmod 440 /target/etc/sudoers.d/admin; \

Thanks!