Blender FBX exporter exports all the bones when deformer only selected

Is it a bug or not? Whenever I export my armature and skinned character mesh with animation and without from Blender 2.83 and tick export only deform bones, all my bone structure being exported to fbx file, even the control bones that have no vertex groups assigned to my character mesh?

If it’s me what are the appropriate fbx export settings to unreal 4? Thanks!

Export settings: