Yup, you did not read wrongly... But it's a saturday, how can it be a school day? Well, this is a normal thing schools do in Malaysia. We often get all these week long holidays predominantly during Chinese New Year and Hari Raya (This is the Muslim New Year - similar to Hanukkah and Xmas). In order to "replace" what has been not taught by having such long holidays, the kids are expected to be back at school on saturdays.
The argument goes both ways - To have or not to have the long holidays. We, Malaysians do uphold more of our traditions as we have more time to celebrate them. The "Balik Kampung" phenomenon (Most working Malaysians work in big cities and visits hometown where the old folks resides) is very common and has stressed our North South Highway to the max during such holidays and traffic jams are notorious.
However, the older folks back home love the visits and hence, it may all be worth it!