Not 'normal' but there are cases there some bags have this quality defect. I don't mean to make you panic more, but this does look like a fairly large misalignment... I guess you'll have it take it into consideration with everything else (leather quality, front flap alignment, overall structure etc.) and see if you want to keep.
That is so true, wondermuffin!! I’m happy that at least it’s on the back where nobody will see it. I put my bag on the authenticity thread, luckily they said it was authentic as well. I always read in articles that Chanel stitching should always be aligned, so I became a bit worriedIt’s not a big flaw enough for me to return this bag. Single flaps are so hard to get, so do think about it for a while.