Generally, all public transport journeys that take place on one day are debited as a total amount from the debit or credit card at the end of the day in question. An exception to this is if your travel costs amount to more than € 50 - in this case, the debit will take place during the day. If you continue to travel after this debit has taken place, then you will see two debits: one on the day of travel, and one after the day of travel.
If you have used two different debit cards that are linked to the same account (for example a plastic debit card and a mobile debit card), then you will also see a separate debit for each of the debit cards on your bank statement. Please make sure that you check out using the same plastic debit card, mobile debit card or smartwatch that you used for checking in. This will help to ensure that you do not end up paying too much.