It is merely a pre-authorization by the banking circuit, which is reported to users that have activated a transaction notification service on their mobile device. Same thing happens when, for example, you refuel at a self-service station. Over the following 24 hours, the correct amount will be charged according to the taps you actually made.

You might be able to see this operation after 3/4 working days, depending on the day of execution of the reversal and on the banking circuit that carries out the operation.