Hey, this is bleu pale, which indeed has tonal stitching. Bleu Brume on the other hand does have white stitching.
It’s my favourite colour and I have several pieces, including a wallet that I sadly had to send to Paris because of the stitching. But in my case the stitching stayed the same and the area around the stitching turned green. Someone showed me a Facebook post of a Kelly that had the same isssue. In the case of the bag Paris actually ended up keeping the bag and offered the owner another one (I think she ended up getting craie / Nata instead). Still waiting to hear back about my wallet.