Yep, I did use a dry iron. I did let it sit longer the second time and I did iron the front and back. It did seem to be sticking at first but then just let go. I live by the water so perhaps the moisture in the air has damaged the glue. Now I am holding a steamy iron over the bocks hoping they will go back in shape as I safety pin it together. I have never free motioned a pinned quilt( this is my 3rd quilt) so it should be interesting.
I have some pieces left that I will try to use in place mats just to see if I can figure out what went wrong. I will definitely stick to spray basting after this.