Copy of .xcf thumbnails does not work

[corrado venturini]

I have a folder with an .xcf (GIMP) image, the image has a correct thumbnail in the nautilus window. When I copy (cut+paste) the image in the same folder the thumbnail is empty.
If I copy the image from a different folder the thumbnail shows the logo of GIMP.
In both cases the thumbnail is WRONG.
Doing the same with a .jpg or .png image the thumbnails are correct.
The same problem happens in Ubuntu 20.04 and 20.10
See the attached image

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: nautilus 1:3.37.1.1-1ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
ApportVersion: 2.20.11-0ubuntu34
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Mon May 18 15:21:24 2020
GsettingsChanges:
 b'org.gnome.nautilus.window-state' b'initial-size' b'(653, 418)'
 b'org.gnome.nautilus.list-view' b'default-column-order' b"['name', 'size', 'type', 'owner', 'group', 'permissions', 'where', 'date_modified', 'date_modified_with_time', 'date_accessed', 'recency', 'starred', 'detailed_type']"
InstallationDate: Installed on 2020-05-11 (7 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Alpha amd64 (20200511)
SourcePackage: nautilus
UpgradeStatus: No upgrade log present (probably fresh install)
usr_lib_nautilus:

[Sebastien Bacher (seb128)]

Thank you for your bug report, could you add a xcf file example to the bug?

[corrado venturini (corradoventu)]

The attached xcf is just a square 100x100 pixel painted in blue.

[corrado venturini (corradoventu)]

Still same problem in Ubuntu 23.04 with nautilus: Installed: 1:44.0-1ubuntu2

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1879330