Drag and drop: incorrect answer... while it's correct

Hi everybody,

Thanks to the community, I now have an almost completely functional drag-and-drop slide.

In short: there are 3 answers, and each one must be dragged onto a designated dropping zone (totaling 3 dropping zones).

Initially, I wanted to display a specific layer ("Non-valid Answer") if a user clicked the Submit button without first moving each answer onto a dropping zone. However, the implementation wasn't perfect.
For instance, if I dropped Answer 1 onto Zone 1, and Answer 2 onto Zone 2, then replaced Answer 2 with Answer 3, Storyline considered that I had moved all three answers. Although this is technically true, Answer 2 had returned to its original position and was no longer on a dropping zone. As a result, clicking on the Submit button showed the "Wrong Answer" layer, when it should have displayed the "Non-valid Answer" layer, since Answer 2 was not on a dropping zone.

Then, Walt from the community provided the attached file that fixed the initial problem (using motion paths) but introduced a new one.
Again, let's say I drop Answer 1 onto Zone 1, Answer 2 onto Zone 2, and Answer 3 onto Zone 3. If I then decide to switch Answer 1 and Answer 2, I move Answer 2 from Zone 2 to Zone 1. This action causes Answer 1 to return to its original position, which is great.
After that, I move Answer 1 from its original position to Zone 2. Now, I have Answer 2 in Zone 1, Answer 1 in Zone 2, and Answer 3 in Zone 3, which is the correct order. However, when I click the Submit button, the "Wrong Answer" layer still appears.

Does anyone have any idea why this is happening?

Thanks a lot.