I just want to thank everyone who offered suggestions on what might be causing my issues. The main causes, in my opinion, were these:
1. The walking foot was installed correctly, however, the stitch-in-the-ditch sole was not seated perfectly. I took off the foot and the sole and put them back on.
2. The batting. I am using Quilters Dream Wool on this quilt. It is a bit thicker than the Hobbs that I have been using.
3. Hand position on quilt. My typical hand positioning combined with the weight and loft of the batting was not giving the quilt enough room to move, even with a high foot position.
Basically, the quilt, even with good weight distribution and support had a little bit too much loft, and weight. So I changed my hand postion to right hand under the quilt and then slightly bunched in the left hand to kind of lift it just a bit when sewing. That helped tremendously and my stitches started coming out more regularly. Because of these issues my stabilization work is not great. Usually, with the SITD sole those stitches are invisible. Not so much this time. But the quilt is for my DH and I know that he will love it no matter what. I am hoping some shrinking and crinkling will hide some of it.
Tomorrow I will begin SITD of the star setting. I am anticipating things going much smoother now that I know what I am up against.
Again, thanks to everyone who commented!