Exporting from any blender version with binary fbx support leads to addition of a redundant bone at root with same name as the armature.
How do I disable addition of that root bone for binary fbx export?
I'm not sure if the bone being exported is infact Blender's armature object (since Blender has an armature object, which can have multiple root bones in the armature).
Seems like this is a known bug, see this report: https://developer.blender.org/T45368 for details.