Hi, Guys! Do you know why some steps we can duplicate and others we don't, even with the session stopped?

Notebook steps are allowed to be duplicated, because the same Notebook isn't allowed to be used by multiple (>1) steps. Reason being: the notebook file is changed in-place when it is executed. Thus if two steps run in parallel but point to the same notebook then two steps would try to write to the same file. This doesn't happen for scripts. Hope that answers your question 😉