Yup! That is what I was about to say. I am glad you figured it out, many people never do. In joining segments, put a vertical pin through where they should all meet, then pin on either side of that.
Also, When I started quilting, the "scant" 1/4" drove me crazy. No one told me that the measure included the hairy edges of the allowance, which makes about 1/32" difference.