help .. some remapped keys is reverting back to its original keys

hello can anyone confirm this or test if it just mine …

in node editor hotkey editor
the Duplicate hotkey is always reverting back to Shift D when i try to change it into other hotkey
even i untick or disable it the check box it keeps comming back to enable

and i save it and triple check it …

its acting like sketchup program ( when changing CTRL S or other hotkey even you save it will revert back when sketchup is restarted

same scenario as blender even i save user preference and save startup it will automatically revert back to default

it it normal? bug?
btw … only in mesh/object mode the duplicate hotkey is fix and doesnt revert back

SOLVE : its strange … i delete my old preference hotkey and load it again and rename it to other file name and it solve the problem …