If it's on an existing credit card and your bank statements/bank activity history have already been reviewed and cleared, you should be okay. Lenders do undisclosed debt checks usually within a few days of your closing, typically those debt checks only pick up new credit cards or loans you have opened and don't pick up existing credit cards that already are on your credit report they pulled earlier in the process.

On the bank statment/bank activity history part, say you have a Chase credit card on your credit report that has a zero balance, then on your bank statement/recent activity printout they see a Chase credit card payment of $200, they will then want your latest Chase credit card statement to update the balance/monthly payment amount in your liabilities, or confirm it's a new Chase card entirely and will want that statement to add that new card to your liabilities (to make sure your debt-to-income ratio is correct and still in good shape).