This is what I would do if facing this situation:
I would take off the walking foot and replace it with a straight stitch foot or, if you have one, a 1/4”foot. I only use my walking foot for straight line machine quilting and attaching the binding. Then I would take out my pins, and pin the edges if they are large squares. If the squares are small, a stiletto (or your seam ripper) can be used to hold the two fabrics even at the end of the seam. This can also help keep the seam allowance straight.
Check your stitch length, and use the length recommended in yiur manual. Mine is about 2.5 for piecing
It is not unusual to need to readjust the ends of the fabrics to keeo them in line. Fabric isn’t wood or concrete. Pins can be your friend, just don’t sew over them.
Last edited by Krisb; 05-20-2018 at 09:28 AM.