Just a guess. Did you print the paper piecing part? Or was it directly from the
magazine? If you downloaded the pattern, chances are when you printed it got
distorted. Not by much but enough to be a nuisance. I have to adjust all my PP
patterns. You could measure the pattern you printed and check if the side of the
square fits the other piece next to it. Hope this makes sense.
I suggest you contact the magazine. They might be able to help you.
I made this block a while ago. You can find this block on the internet
but I'm not sure if you will be able to find all sizes. Then you get into
the same problem...download and print is 99% of the time distorted.
Some might not have this problem but I always do. Good luck.