I have a RecyclerView that expands the following grid item :
Your SquareImageView is filling up the entire space (width is match_parent and height is wrap_content) and so the SquareImageView receives the click event.
What worked in my case was setting the clickable state of all objects in your RelativeLayout to false:
android:clickable="false"
Just make sure your RelativeLayout handles the click event in your activity. In my code I set the RelativeLayout to a view v and set an onClick Listener on it to handle the CheckBox within my List item.
v.setOnClickListener(this);
Hopefully this helps anyone who reads it.