Steps to reproduce:

print:~ # truncate -s 10M disk.image
print:~ # fdisk disk.image

Welcome to fdisk (util-linux 2.31.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x1245ac3a.

Command (m for help): w
The partition table has been altered.
Syncing disks.

print:~ # fdisk -l disk.image
Disk disk.image: 10 MiB, 10485760 bytes, 20480 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x1245ac3a
print:~ # losetup --list
print:~ # kpartx -l disk.image 
print:~ # losetup --list
NAME       SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE        DIO LOG-SEC
/dev/loop0         0      0         0  0 /root/disk.image   0     512

???
Why does kpartx -l leave behind a loop device on the inspected image?
???


print:~ # cat /etc/os-release 
NAME="openSUSE Leap"
VERSION="15.0"
ID="opensuse-leap"
ID_LIKE="suse opensuse"
VERSION_ID="15.0"
PRETTY_NAME="openSUSE Leap 15.0"
ANSI_COLOR="0;32"
CPE_NAME="cpe:/o:opensuse:leap:15.0"
BUG_REPORT_URL="https://bugs.opensuse.org"
HOME_URL="https://www.opensuse.org/"
print:~ # uname -a
Linux print 4.12.14-lp150.12.16-default #1 SMP Tue Aug 14 17:51:27 UTC 2018
(28574e6) x86_64 x86_64 x86_64 GNU/Linux
print:~ # rpm -q kpartx
kpartx-0.7.3+67+suse.8f0c27b-lp150.1.1.x86_64


The same behaviour occurs with Tumbleweed 20180831.