Reproduces in every version of Shadergraph going back to 4.10.1
Steps to repro:
1. Open a shadergraph
2. Create any node
3. Move the node
4. Click drag on one of the inputs or outputs of the node, drag the edge out into empty space
5. While continuing to hold the mouse button, ctrl.z

Expected result: the edge is cancelled
Actual result: A ghost edge is created

If you drag over the output of another node instead of empty space, selecting the ghost edge will print debug logs to console: "Selected Ghost Edge: this should never be"

If you undo a node creation in VFX graph while dragging an edge out in the same way, the same bug happens.