Corruption for etc/pam.d/ftpd when running etcupdate for 14.3 to 15.0

Hello, I'm observing corruption or bad merge for some files when
manually upgrading from 14.3 to 15.0 with etcupdate.

This looks like a bug in etcupdate. Can someone please confirm this?

UPDATE_ROOT="/mnt"
BENAME=15.0

# Create and mount new boot environment
bectl create ${BENAME:?}
bectl mount ${BENAME:?} ${UPDATE_ROOT:?}

# Perform base + kernel update
...

# Perform etc update

# 1) Extract etcupdate current tree from the base archive
tar -xpf base.txz ./var/db/etcupdate/current

# 2) Create etcupdate.tar.bz2 archive
tar -C ./var/db/etcupdate/current -jcf etcupdate.tar.bz2 ./ && rm -rf ./var

# 3) Run etcupdate merging new changes in etcupdate.tar.bz2 into /etc
etcupdate -D ${UPDATE_ROOT:?} -d ${UPDATE_ROOT:?}/var/db/etcupdate -F -t etcupdate.tar.bz2

After the above steps I end up with broken /mnt/etc/pam.d/ftpd. The
original file from 14.3 in /etc/pam.d/ftpd was never even modified.

All the other files in /etc seem to be OK according to:
etcupdate diff -D ${UPDATE_ROOT:?} -d ${UPDATE_ROOT:?}/var/db/etcupdate

cat /mnt/etc/pam.d/ftpd
#
# PAM configuration for the "ftp" service.  This is not used by the FreeBSD
# ftpd(8), but is provided for compatibility with FTP servers from ports.
#

# auth
auth            include         ftpd

# account
account         include         ftpd

# session
session         include         ftpd