I am having trouble on HTC One m7 GPE running android lollipop. After I am done using the player, the playback controls no longer show on the notification/lock screen (this is what I would expect). The problem is that at some random time later (usually within an hour) the playback controls shows back up in the notifications area and cannot be dismissed or hidden.
It seems to me it should behave more like the google music app which only shows in the notification while playing or paused, and if it is paused it can be dismissed.