I got my statement at 21 of December, but was at flight, and I had -35.5 USD balance on my credit card. Next day (22) I made a payment (by 2 transactions) to hit it to 0, and set payment to be processed at next day (23). But now my credit card shows me there is -71 USD on balance while transactions from other account show -35 USD withdrawal. What happened? There is no additional notifications and whatever. Just 2 transactions on both accounts for same amount (same Bank).
You had a $35.50 credit for whatever reason. You got the statement, paid another $35.50, now have a $71 credit. Go fill up the gas tank a couple times and don’t worry about this. (Note: for those of us who use the card regularly, these credits, the potential of the bank owing us money, doesn't last long.)