Both notifications are permanent so neither can be dismissed. Only one has an event hook to update the track position every second but the other does refresh to the current position when the notification tray is pulled down. When playback is stopped one disappears after a period of time but the other stays and can only be removed by pressing its stop button.
I have submitted debug log UGNZ4UIJ3I shortly after the second time this occurred.
MMA 461 running on a Nexus 6 with stock Android 5.1.1.
