It will just count as $0. Best thing to do since you know the refund will come back is to just spend $4k as you normally would ignore your canceled ticket transactions. Pretend they never happened.

Side note: I also canceled a airline ticket within 24 hours, I got charged and the charge was actually posted to the card. The refund came back roughly after 7 business days or so. (this was on a sapphire preferred card)