It might happen for custom checkout flows. Can you spot the differences between orders that have the id attached and ones that do not have?
Thank you for your reply!
I already checked and there isn't custom checkout flow.
One of the issue is may be
[landing_site] => /wallets/checkouts.json
is always same, how is that possible? I think this is when customer checkout using directly "Buy Now" button.
Is there any way to get correct landing_site even if used "Buy Now" button?