Well, here is the result of sewing them as they were placed. I'm guessing that the smallest blue triangle is not the right size (too small) and I cut the others in that block to that size to get the triangle effect. I'll cut that larger (their directions must still be wrong!) and see what happens.
I checked and rechecked the directions and my cutting. That triangle is cut from a 2 1/8 inch square. I can't understand why no one has pointed out to them that this is inaccurate.
(I just sent them an email but don't expect a reply.)