Comment 14 for bug 1841137

This is happening on an up-to-date (as of 2020 Apr/30) Eoan with
$ snap --version
snap 2.44.3
snapd 2.44.3
series 16
ubuntu 19.10
kernel 5.3.0-46-generic

>>> 15:55:37 andre@thinkpad ~
$ losetup -l
NAME SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE DIO LOG-SEC
/dev/loop1 0 0 1 1 /var/lib/snapd/snaps/core_8935.snap (deleted) 0 512
/dev/loop29 0 0 1 1 /var/lib/snapd/snaps/lxd_14729.snap (deleted) 0 512
/dev/loop19 0 0 1 1 /var/lib/snapd/snaps/gtk-common-themes_1506.snap 0 512
/dev/loop27 0 0 1 1 /var/lib/snapd/snaps/lxd_14709.snap (deleted) 0 512
/dev/loop8 0 0 1 1 /var/lib/snapd/snaps/core18_1705.snap 0 512
/dev/loop25 0 0 1 1 /var/lib/snapd/snaps/lxd_14663.snap (deleted) 0 512
/dev/loop15 0 0 1 1 /var/lib/snapd/snaps/lxd_14555.snap (deleted) 0 512
/dev/loop6 0 0 1 1 /var/lib/snapd/snaps/openstackclients_38.snap 0 512
/dev/loop33 0 0 1 1 /var/lib/snapd/snaps/gnome-3-34-1804_27.snap 0 512
/dev/loop23 0 0 1 1 /var/lib/snapd/snaps/lxd_14639.snap (deleted) 0 512
/dev/loop4 0 0 1 1 /var/lib/snapd/snaps/gnome-calculator_730.snap 0 512
/dev/loop31 0 0 1 1 /var/lib/snapd/snaps/juju_11454.snap 0 512
/dev/loop21 0 0 1 1 /var/lib/snapd/snaps/lxd_14583.snap (deleted) 0 512
/dev/loop11 0 0 1 1 /var/lib/snapd/snaps/charm_461.snap 0 512
/dev/loop0 0 0 1 1 /var/lib/snapd/snaps/lxd_14877.snap (deleted) 0 512
/dev/loop28 0 0 1 1 /var/lib/snapd/snaps/code_31.snap 0 512
/dev/loop18 0 0 1 1 /var/lib/snapd/snaps/lxd_14594.snap (deleted) 0 512
/dev/loop9 0 0 1 1 /var/lib/snapd/snaps/lxd_14804.snap (deleted) 0 512
/dev/loop16 0 0 1 1 /var/lib/snapd/snaps/lxd_14680.snap (deleted) 0 512
/dev/loop7 0 0 1 1 /var/lib/snapd/snaps/gnome-characters_495.snap 0 512
/dev/loop34 0 0 1 1 /var/lib/snapd/snaps/lxd_14890.snap 0 512
/dev/loop24 0 0 1 1 /var/lib/snapd/snaps/lxd_14649.snap (deleted) 0 512
/dev/loop14 0 0 1 1 /var/lib/snapd/snaps/gnome-logs_93.snap 0 512
/dev/loop32 0 0 1 1 /var/lib/snapd/snaps/core_9066.snap 0 512
/dev/loop22 0 0 1 1 /var/lib/snapd/snaps/lxd_14611.snap (deleted) 0 512
/dev/loop30 0 0 1 1 /var/lib/snapd/snaps/lxd_14759.snap (deleted) 0 512
/dev/loop10 0 0 1 1 /var/lib/snapd/snaps/gnome-3-28-1804_116.snap 0 512
>>> 15:56:00 andre@thinkpad ~
$ snap list
Name Version Rev Tracking Publisher Notes
charm 2.7.4 461 latest/stable canonical✓ classic
code ff915844 31 latest/stable vscode✓ classic
core 16-2.44.3 9066 latest/stable canonical✓ core
core18 20200311 1705 latest/stable canonical✓ base
gnome-3-28-1804 3.28.0-16-g27c9498.27c9498 116 latest/stable/… canonical✓ -
gnome-3-34-1804 0+git.2c86692 27 latest/stable canonical✓ -
gnome-calculator 3.36.0+git4.51b0dc05 730 latest/stable/… canonical✓ -
gnome-characters v3.32.1+git4.e06f0b2 495 latest/stable/… canonical✓ -
gnome-logs 3.34.0 93 latest/stable/… canonical✓ -
gtk-common-themes 0.1-36-gc75f853 1506 latest/stable/… canonical✓ -
juju 2.7.6 11454 latest/stable canonical✓ classic
lxd 4.0.1 14890 latest/candidate canonical✓ -
openstackclients train 38 latest/stable james-page classic

Also, all those volumes are appearing as mountable devices in Files app. And trying to delete them manually with losetup -d will not work.