There is no real notion of an "empty" event in SGPro. If it exists, it can be executed. The one exception is when a CFW is connected, but no filter is defined. Like this:
The "None" refers to the selected filter. Then when you run the sequence you get this:
Is this what you mean? It is hard for me to interpret from your description.
Once I acknowledge this, untick the event 5 box and click, run, the sequence starts without issue.