Atraso de 25 segundos: "Nenhum esqueleto para exportar"

Preso por um bom tempo com o problema de que o lançamento de aplicativos GNOME causa um atraso de exatamente 25 segundos. Espero que alguém possa ler este trecho do syslog melhor do que eu; o que são "monitor de fundo", "proxy secreto" e "esqueleto para exportar" é um mistério total para mim.

Transcrição do syslog ( rtkit-daemonentradas retiradas):

2023-12-01T16:55:43.335760-08:00 dowland dbus-daemon[209261]: [session uid=1000 pid=209259] Activating service name='org.freedesktop.portal.Desktop' requested by ':1.1041' (uid=1000 pid=1410414 comm="evince ibook.pdf")
2023-12-01T16:55:43.344016-08:00 dowland dbus-daemon[209261]: [session uid=1000 pid=209259] Activating service name='org.freedesktop.portal.Documents' requested by ':1.1042' (uid=1000 pid=1410419 comm="/usr/libexec/xdg-desktop-portal")
2023-12-01T16:55:43.344099-08:00 dowland dbus-daemon[209261]: [session uid=1000 pid=209259] Successfully activated service 'org.freedesktop.portal.Documents'
2023-12-01T16:55:43.345334-08:00 dowland org.freedesktop.portal.Documents[1410430]: fusermount3: failed to access mountpoint /run/user/1000/doc: Permission denied
2023-12-01T16:55:43.345466-08:00 dowland org.freedesktop.portal.Documents[1410424]: error: fuse init failed: Can't mount path /run/user/1000/doc
2023-12-01T16:55:43.360001-08:00 dowland xdg-desktop-por[1410419]: value "((GDBusConnectionFlags) G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT | G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION | 64)" of type 'GDBusConnectionFlags' is invalid or out of range for property 'flags' of type 'GDBusConnectionFlags'
2023-12-01T16:55:43.360077-08:00 dowland xdg-desktop-por[1410419]: Failed to create background monitor: The connection is closed
2023-12-01T16:55:43.360138-08:00 dowland xdg-desktop-por[1410419]: No skeleton to export
2023-12-01T16:55:43.361944-08:00 dowland dbus-daemon[209261]: [session uid=1000 pid=209259] Activating service name='org.freedesktop.secrets' requested by ':1.1042' (uid=1000 pid=1410419 comm="/usr/libexec/xdg-desktop-portal")
2023-12-01T16:55:43.364847-08:00 dowland gnome-keyring-d[1281]: The Secret Service was already initialized
2023-12-01T16:55:43.366081-08:00 dowland org.freedesktop.secrets[1410435]: discover_other_daemon: 1
2023-12-01T16:56:08.387485-08:00 dowland xdg-desktop-por[1410419]: Failed to create secret proxy: Error calling StartServiceByName for org.freedesktop.secrets: Timeout was reached
2023-12-01T16:56:08.387739-08:00 dowland xdg-desktop-por[1410419]: No skeleton to export
2023-12-01T16:56:08.389574-08:00 dowland dbus-daemon[209261]: [session uid=1000 pid=209259] Successfully activated service 'org.freedesktop.portal.Desktop'
2023-12-01T16:56:08.427842-08:00 dowland dbus-daemon[209261]: [session uid=1000 pid=209259] Activating service name='org.gnome.evince.Daemon' requested by ':1.1041' (uid=1000 pid=1410414 comm="evince ibook.pdf")
2023-12-01T16:56:08.430806-08:00 dowland dbus-daemon[209261]: [session uid=1000 pid=209259] Successfully activated service 'org.gnome.evince.Daemon'

Versões de software (Debian instável, recém atualizado):

dbus-daemon                               1.14.10-1~deb12u1
gnome-keyring                             42.1-1+b2
xdg-desktop-portal                        1.16.0-2
xdg-desktop-portal-gnome                  43.1-2
xdg-desktop-portal-gtk                    1.14.1-1
xdg-utils                                 1.1.3-4.1

Não tenho ideia do que /run/user/1000/docdeveria ser, mas já está montado:

portal on /run/user/1000/doc type fuse.portal (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)