Operating system: Linux
Graphics card: GeForce 1050
version: 2.80 (sub 44), branch: blender2.7, commit date: 2019-02-11 23:10,
hash: 036ec5cae4f7, type: Release build date: 2019-02-12, 00:32:25
Short description of error
shift-D to duplicate armature makes only shallow copy:
one gets a new armature, but it points to the same bones.
Exact steps for others to reproduce the error
Based on attached .blend file:
(trying to get two separate armatures, one for Left, and one for Right).
pivot mode: 3D-cursor
shift-C: center cursor at origin
Outliner: select "Armature.Hand.L" from Hand.L collection
shift-D, Enter: duplicate in place.
menu: Armature » Mirror » X-Global
The armature appears mirrored at this point, but .L-->.R name flipping doesn't happen.
Going to Object Mode flips the new armature back to a left-hand version.
Inspecting Outliner shows that a new armature was created, but no new bones.
Outliner » RMB (new Armature.Hand.L.001) » ID Data » Make Single User
has no effect.
I would have expected an alt-D option to make a linked duplicate, but there is no alt-D option in the Armature menu.