Drag and Drop issue

Creating a Hover state for an object  gives it superpowers, one of which is to automatically change to the Hover state when the cursor hovers over it. When you create another trigger that duplicates that action, it frequently conflicts with the built-actions. The results of those conflicts are unpredictable, sometimes spectacular, but almost always undesireable. In this case, they cause the error message you are seeing. Delete all those "hover" triggers, and see if it works.

An additional fact is that all the states on the drop-down name menu for new states behave the same way - they can handle their native function, and resent any interference. :)