Whenever the boot process is a bit slow, gsd-media-keys quickly gives up trying to grab keyboard shortcuts. Later, even though the method call eventually reaches gnome-shell just fine, gsd-media-keys doesn't know what to do with the notifications.

gsd-media-keys[1178]: Failed to grab accelerators: Timeout was reached (24)
gsd-media-keys[1178]: Could not find accelerator for accel id 153
gsd-media-keys[1178]: Could not find accelerator for accel id 153
gsd-media-keys[1178]: Could not find accelerator for accel id 153

On my work PC (with Dropbox and Tracker booting off a HDD...), this happens approx. 3/4 of the time. Maybe the timeout should be increased, or gsd should retry when it receives G_DBUS_ERROR_TIMED_OUT? (I see it already has a retry loop.)

gnome-settings-daemon 3.26.x