When passing the presented vehicle are you obliged to exercise particular caution?

Yes, you must exercise special care. The vehicle you are overtaking is marked with a blue plate with the letter "L", which means it is a learner driver vehicle. The learner driver may behave unpredictably, for example, by braking sharply or having trouble maintaining their lane. This obligation arises from Art. 55 para. 3 of the Road Traffic Act.