Making a Drag and Drop Score as Correct Using Triggers

This is way too complex for description. Without seeing it, I can't imagine how the learner can drag something off the screen before dropping it. How does drop1 change to Drop Correct state if it isn't dropped?

I have two suggestions. Either create a sanitized version of just that slide and post it here, or see if you can get any ideas from the sample at this post:
https://community.articulate.com/discussions/articulate-storyline/drag-and-drop-solution-sample-with-multiple-correct-targets-with-drag-off-and-return-plus-a-lot-more 

I doubt that it will help you, because all the dragging action takes place on the screen.