Scale

The slide has 6 rows/sets of buttons, but it only has 3 button sets. 

Assigning buttons to the wrong set is what is causing some answers to be deleted. For example, the second button in set 4 is in button set page1-set1. Selecting that button will automatically deselect all of the other buttons in that set. 

For this type of interaction, each row of buttons needs to be in its own button set. 

That has been done in the edited slide in the attached file.

Also notice that I rearranged items in the Timeline so that the buttons in each set are together.

This makes it easier to select the correct buttons for each set.