Comment 0 for bug 1765380

1) lsb_release -rd
Description: Ubuntu Bionic Beaver (development branch)
Release: 18.04

2) apt-cache policy busybox
busybox:
  Installed: 1:1.27.2-2ubuntu3

3+4) preseed installation on Bionic, late_command almost the same in Xenial and there is working

preseed.cfg
d-i preseed/late_command string /tmp/late_command

ls -l /bin/sh
lrwxrwxrwx 1 root root 4 Sep 26 2014 /bin/sh -> busybox

syslog:
running: /tmp/late_command

nothing happend on shell:
/tmp/late_command

head late_commaand
#!/bin/sh
printf '' > /usr/lib/finish-install.d/55netcfg-copy-config;

in-target mkdir -p /opt/MegaRAID/MegaCli/;
in-target mkdir -p /root/.ssh;
in-target mkdir /etc/check_mk;

So is there a bug in busybox sh?
How can I debug busybox sh script.sh?