Rebar removed when running script..?

Good morning.
I have the following problem.
I am working within dynamo and I have created a script that creates reinforcements in structural frames, but it happens that when I run the script the script creates the code and when I run it again and select other elements it creates some reinforcements but deletes the previously created ones, despite What do I save and close Revit and reopen and run the script? It still deletes the previously created ones, why is that?

This is element binding.

See this post: Element Binding in Revit