System Information
Operating system: Windows 10 Home
Graphics card: Nvidia GTX 1080

Blender Version
Broken: (example: 2.80, edbf15d3c044, master, 2018-11-28, as found on the splash screen) blender-2.80-e8daa615704b-win64
Worked: (optional)

Short description of error
Duplicate function not working as usual

Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
Just Duplicate "Default Cube" with Shift D or Duplicate Linked with Alt D
Now drag with mouse the new duplicated cube, and original cube is affected too!