The Details dialogue adds XMP tags instead of reloading if EXIF tags are absent
It can be reproduced in the following way.
Get one or several images that have both EXIF and XMP tags. The images that I used in my test can be downloaded from Wikimedia Commons (link1, link2, link3) and NASA (link).
Get an image that has XMP tags but does not have EXIF tags. For example, you can download one from Wikimedia Commons (link). Alternatively, you can create one from an image that has both EXIF and XMP tags by wiping EXIF tags with exiftool
like this:
$ exiftool -exif:all= target_image.jpg
Open your image to take a look at its metadata with the "Details" dialogue. You may keep the window and the dialogue open for later reference.
Have all test images in one directory. Open an image that you know that it has both EXIF and XMP tags with the viewer. Open the "Details" dialogue with the "Show Details" button under the contents of the "Properties" sidebar. Get the main window in focus without closing the "Details" dialogue and move to another image until you know that it has only XMP tags but no EXIF tags. Get the "Details" dialogue back in focus. You may notice that the "Details" dialogue was reloading each time you switched the image in the viewer (if you were keeping an eye on it or explored it each time) but, the moment you switched to the image with XMP tags without EXIF tags, it added the XMP tags of that image to the tags of the previous image and misleadingly shows them combined. Explore the groups in the "Details" dialogue to verify.
Note: If the image has neither EXIF nor XMP tags, the "Details" dialogue is reloaded as expected and shows an empty window with a warning. To test this, you can also wipe the XMP tags similarly with exiftool -xmp:all=
and repeat the test. So the tags from the previous image are erroneously shown only if the problematic image has XMP tags but no EXIF tags.
Tested on Fedora Linux 37 (Workstation Edition) with: GNOME Image Viewer 43.1 GNOME Image Viewer 44.rc from gnome-nightly flatpak