Piecing thread tension
I have a number of HST made as leaders and enders. These pieces were often the first sewn after I put in a new bobbin or spool of thread and for some of them the thread tension was not quite right. Do I need to throw these out or can they be used in a scrap quilt if I use them in blocks where the seams are crossed? Is there any harm in using them or are they likely to fall apart when the quilt is used?
I think it depends on what you mean by "not quite right." How does the seam look? Try pulling on the seam and see how it acts.
If the tension is too loose, just sew over them and press. No one will be able to tell.
I would run over the seams once more and then use them.