How to handle a pick many option if a user picks none

I've done my very best with this one, but I'm defeated. I'm sure at this point that I'm overlooking something very obvious.

Here is my challenge.

I have a question slide where users are given sentences with potentially incorrect commas. They click on a comma to "delete" it (which I handle by making it disappear when "selected.")
Everything is fine with that. But here's my issue:
A user might believe that the correct option is to select none of the commas. It's a valid possibility (even though, in fact, all questions require at least one deletion). I realized that if they did that, clicking Submit would result in the "Please answer the question" message.
So to avoid a clunky solution where they have to click a button saying "don't delete any" or something, I got inventive and added a hidden object to the slide (which I did include in the Enter the Choices list as a wrong choice). I set triggers so that the object would be select if the state of all the other objects listed in the Enter the Choices list (i.e. the commas) were Normal (i.e. untouched):

Change state of Button 2 - "No deletions" to Selected
When the user clicks submit
If the state of picture 4 = Normal
AND the state of Picture 5 = Normal

I made sure the triggers preceded the Submit pick many trigger.

It worked in that the "incorrect" message was displayed if the user did not select any of the commas for deletion.

But then I found it messed up the correct answer. If you make the correct choice now, you get the "incorrect" message. In exposing the "No deletions" button so I can see what's going on, I can see it always changes to Selected when I click submit no matter what the state of the other "commas" is. 

By my logic it should only change to selected IF both of the commas are still Normal.
I've tried various version of accomplishing the same thing--as well as absolutely everything I can think of. 
Can anyone help me find an elegant solution to showing an "incorrect" feedback layer when a user picks none in a pick many question rather than showing a "please complete the question" message?
Thanks! (I'm working in Storyline 360)