Are you building from inside a container? You might need to pass --disable-rofiles-fuse to flatpak-builder: Makefile: Disable rofiles-fuse when run in a container (e19fc74f) · Commits · Packaging / Flatpak KDE Runtime · GitLab
Are you building from inside a container? You might need to pass --disable-rofiles-fuse to flatpak-builder: Makefile: Disable rofiles-fuse when run in a container (e19fc74f) · Commits · Packaging / Flatpak KDE Runtime · GitLab