Panadol night is a GlaxoSmithKline painkiller intended for use at night. It consists of 500 milligrams of paracetamol, 25 milligrams of diphenhydramine hydrochloride (a sedating antihistamine) and other "non-hazardous ingredients" It is sold in Australia, Cyprus United Kingdom, Ireland, New Zealand and the Middle East. It became available as an over the counter medication in the UK in 1996.
Panadol night was available as an over the counter medication in the UK at the start of the 21st century
The context states that Panadol night became available as an over the counter medication in 1996, which is near the end of the 20th century. Therefore, when the 21st century began a few years later, Panadol night was available over the counter in the UK and had been for a few years. The computer might have been confused because the context doesn't mention centuries at all. 