--- Operating System, Graphics card ---
Windows 7 64bit,

--- Blender version with error, and version that worked ---
current (or all) versions with issue

--- Short description of error ---
when i create a 'ShaderNodeGroup' (+'NodeGroupOutput'+'NodeGroupInput') via script, i can not access its outputs and inputs by its names, even their names are unique, and visible when i iterate them by script.
i alwasy have to use the indices to get them.

node.inputs['blablabla'] -> fails
node.inputs[0] -> works

(even when node.inputs[0].name -> 'blablabla', or node.inputs[0].identifier is set)


--- Steps for others to reproduce the error (preferably based on attached .blend file) ---
1. accessing by index
1.1. open the attached blend file
1.2. run script
1.3. it works

2. accessing by name (.outputs[key] or .outputs.get(key))
2.1. open the attached blend file
2.2. uncomment the test_case item 'BY_KEY' or 'BY_GET'
2.3. run script
2.4. it fails