I have a strange issue with the sewing when I am working with a graded pattern. I think it might be a bug, but if not it would be great if someone could help me on what to do here.

I have a men's pant graded (outside of Clo) in sizes 30-42. Sewing in most areas are fine, except on certain pieces like the front and back pocket bags and the pocket facing. The sewing at the top edge of these pieces is fine in size 30, but as I check each size the sewing on the other line (the part the pocket pieces are attached to) are grading, while the stitch line on the pocket pieces is staying as the original. This is causing puckering and stitching length not matching on just these areas. 

It's pretty hard to explain so I am including some screen shots to show what is happening physically. Is there a way to make the one stitching line not grade, or to lock the length of the stitching for these pieces? I tried right clicking and selecting link line, but this did nothing. I am not even sure what this action is supposed to do. 

Along with linking, I tried sewing the pocket bag pieces to the pant, then the waistband. Doesn't seem to matter how I attach it, the sewing lengths get misaligned on different sizes. I could eliminate the pocket bags but this wouldn't help the situation with the pocket facing piece at the side as this piece is necessary. And this file has already been simplified enough for performing the grade review without eliminating even more construction details.

Please help, I need to complete this style with full grading review for a client.

Thank you.