Error: "Failed to register AppImage in system via libappimage" on first run

[bobhy]

Downloading an AppImage from the continuous build (16-May-2025), then making it executable and trying to integrate it via AppImageLauncher fails with popup:

repro:

$ wget https://github.com/AppImageCommunity/AppImageUpdate/releases/download/continuous/AppImageUpdate-x86_64.AppImagee

... clip ... (the above path is the continuous build release)

2025-08-03 20:23:55 (782 KB/s) - ‘AppImageUpdate-x86_64.AppImage.1’ saved [48638456/48638456]

--------------------------------------------------------------------------------- /tmp ---------------------------------------------------------------------------------
$ chmod u+x AppImageUpdate-x86_64.AppImage.1
--------------------------------------------------------------------------------- /tmp ---------------------------------------------------------------------------------
$ ./AppImageUpdate-x86_64.AppImage.1 
QSocketNotifier: Can only be used with threads started with QThread
Squashfs image uses (null) compression, this version supports only xz, zlib.
ERROR: appimage_shall_not_be_integrated : sqfs_open_image error: /tmp/AppImageUpdate-x86_64.AppImage.1
AppImageLauncher error: appimage_shall_not_be_integrated() failed (returned -1)
Squashfs image uses (null) compression, this version supports only xz, zlib.
ERROR: appimage_is_terminal_app : sqfs_open_image error: /tmp/AppImageUpdate-x86_64.AppImage.1
AppImageLauncher error: appimage_is_terminal_app() failed (returned -1)
Squashfs image uses (null) compression, this version supports only xz, zlib.
ERROR: appimage_register_in_system : sqfs_open_image error: /home/bobhy/Applications/AppImageUpdate-x86_64.AppImage_6c7e24c818b4ef7d17373f07f1a59854.1

Same procedure, but with path:

$ wget https://github.com/AppImageCommunity/AppImageUpdate/releases/download/2.0.0-alpha-1-20241225/AppImageUpdate-x86_64.AppImage

Works OK.

Maybe a CI problem?

Environment

Ubuntu Plucky
AMD Ryzen 9