When you use your HyperJar card to 'pay-as-you-go' for travel on mass transit systems such as the bus, London Underground etc, you may see a 10p charge when the fare was much bigger or a charge at odd times like 2 am. They are perfectly normal and nothing to worry about.
The 10p charge (or sometimes a 1p charge) is called an authorisation charge and it is how the company checks that the card is valid and works. After your journey, this 10p charge is taken off when the full cost of your travel is charged.
If you see a bus or train fare taken at 2 am don't worry: it doesn't mean your card's been stolen. Companies have to pay a charge when they take payment from you. To reduce costs, most transport companies wait until the end of the day and add all your travel up into one payment.