Issue with song displaying

[LGnap]

When using "action buttons" in the applet or through an external controller like mpc. The song displayed into applet doesn't change anymore.
But the data pass through the dbus-monitor and the applet create/show a notification about the new song played at the top of the screen.
In addition to that the seek system doesn't work also.

I found nothing interesting into dbus-monitor except maybe instruction for seeking

method return time=1455046443.605539 sender=:1.7 -> destination=:1.15 serial=139 reply_serial=795
   boolean true
method call time=1455046446.032168 sender=:1.15 -> destination=:1.65 serial=796 path=/org/mpris/MediaPlayer2; interface=org.mpris.MediaPlayer2.Player; member=SetPosition
   object path "/org/mpris/MediaPlayer2/Track/1561"
   int64 254287392
method return time=1455046446.032582 sender=:1.65 -> destination=:1.15 serial=173 reply_serial=796