It looks like you may not have a large enough seam allowance and the green fabric looks very soft and thin. I had this happen on some of my first quilts. It was because of poor fabric quality in my case. I started out quilting using scraps and that was when I learned about using good quality fabric in a quilt. The good scraps did not do this, only the bad scraps. I zig zaged over the rips and went on to making the next quilt.