Copy-pasting custom property nodes (ControRig etc.) results in invalid bindings, perf issues

From this UDN:

[Link Removed]

Suggested fix:

1. Override PostPasteNode to perform the GUID update and
2. Add validation on load to strip 'invalid' copies that do not correspond to a valid pin input

Create a ControlRig node, choose the rig class and expose some pins 

Right click the exposed pins to bind them via property access

Copy-paste the node into the same graph - see that the bindings are no longer visible

Paste into text editor - see that the bindings are still present, but their PropertyName is incorrect (wrong node GUID)