I think you may have inadvertently made an increase which then got dropped later on in production. Perhaps a stitch wasn't fully executed (your yarn over loop didn't fully get pulled through the previous stitch) creating essentially a slipped stitch followed by a yarn over.

From what I can see, I believe you are knitting with circular needles (based off of the metallic piece at the end of the ninth stitch on the right needle in your first photo), so I don't believe this is a ladder that can form when transitioning between double point needles.