Good morning, 

after closing VLC, the media keys incorporated in the keyboard (play/stop/previous/next) become ignored by any other process. 

Listening to dbus-monitor reports:

signal time=1525366416.827107 sender=:1.14 -> destination=:1.42 serial=2127 path=/org/gnome/Shell; interface=org.gnome.Shell; member=AcceleratorActivated
   uint32 158
   array [
      dict entry(
         string "device-id"
         variant             uint32 3
      )
      dict entry(
         string "timestamp"
         variant             uint32 4146816
      )
      dict entry(
         string "action-mode"
         variant             uint32 1
      )
   ]
method call time=1525366416.827800 sender=:1.42 -> destination=org.mpris.MediaPlayer2.vlc.instance3242 serial=157 path=/org/mpris/MediaPlayer2; interface=org.mpris.MediaPlayer2.Player; member=Next
error time=1525366416.827834 sender=org.freedesktop.DBus -> destination=:1.42 error_name=org.freedesktop.DBus.Error.ServiceUnknown reply_serial=157
   string "The name org.mpris.MediaPlayer2.vlc.instance3242 was not provided by any .service files"

VLC v3.0.1, ARCH-Linux, gnome v3.28.1, gstreamer 1.14.0-1.

I've previously opened a related bug against VLC, but it has been promptly closed: https://trac.videolan.org/vlc/ticket/20411#comment:2

In case let me know against which component this bug should be addressed.