System Information
Operating system: Windows-10-10.0.19042-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1660/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 472.84
Blender Version
Broken: version: 3.2.0 Alpha, branch: master, commit date: 2022-04-14 19:51, hash: rB48ff456a4bda
Worked: N/A
Short description of error
Unlike other elements like faces and points, edges duplicated with Duplicated Elements node are not displayed in the viewport. They are there, as you can continue manipulating them down the node tree fine, they're just not shown.
They don't become visible until you apply the Geometry Nodes modifier, and enter into Edit Mode:
Exact steps for others to reproduce the error
Add a Geometry Nodes modifier to a mesh object, and drop a Duplicate Elements in between the group input and output. Set it to Edge. Nothing will be shown in the viewport.