Keeping in mind that clones share information while duplicates are independent copies, problems may arise when you believe you are working with a clone instead of a duplicate and vice versa.
"By default, when you select a node in the Node view and perform a copy/paste using Ctrl + C and Ctrl + V (Windows/Linux) or ⌘ + C and ⌘ + V (Mac OS X), this creates a CLONE not a duplicate. Nodes will be linked to the same drawings. Pegs will be linked to the same function columns.
To duplicate a layer in the Node view using keyboard shortcuts, press Ctrl + C (Windows/Linux) or ⌘ + C (Mac OS X) and Ctrl + B (Windows/Linux) or ⌘ + B (Mac OS X) for Paste Special, and in the Advanced tab, select Nodes: Create New Columns."
Above text found in Harmony 12 documentation here under How to clone a layer:
Above text found in Harmony 14 documentation here under How to clone a layer: