Invalid Answer - You must complete the question before submitting (Pick Many)

After lots of frustration with the Invalid Answer pop-up, I realized SL wasn't recognizing when an item was clicked. It thought I was submitting the question without having selected anything.

Looks like the solution (or at least one solution) for a Freeform Pick Many question is to NOT create any custom triggers or multiple states. SL360 is smart enough now (compared to SL3) to recognize what should happen. I stripped my question down to bare essentials: just 2 states (Normal & Selected) on the clickable items and No custom Submit button. I didn't add any additional triggers. The only trigger I now have is the default "Submit Button" Player Trigger: "Submit interaction Pick Many When the user clicks submit." 

Also, when I copied & pasted an item -- WITH ITS EXSTING TRIGGERS -- I seem to have issues. These were copied & pasted from different question types, so that MAY be another factor. Once I inserted all new clickable items, that seems to have solve the Invalid Answer issue.

It works fine now.