Advice?

Hello, I am looking for some advice regarding backpacks. I truly have been able to fix most every issue over the years but I am having no luck.

I have tried using adjusting my frame (for backpacks) changing my needle, changing my fonts, removing underlay, changing density, checking that tensions are good.

What else could the attached pictured issue could be causing this to move out of line as shown? I have done a test sew out and it sews fine but no matter what I change it sews wonky on the backpack.

Thank you for any help, advice and/or comments.