There are many well-known design errors, such as the Fiji "empty canoe", France "discours sur la méthode" and many stamps showing Columbus using a telescope.
How about some lesser known design stuff ups? How can these errors get past the first approval process???
South Africa 1949 "Settlers", depicting a scene from 1849, and showing a radio mast on the hill
In 2011, a booklet was issued in GB for sale by Historic Scotland. The fourth stamp shows the Ring of Brodgar on Orkney. Except it doesn't. These are the Calanais (Callanish) Stones, located on Lewis, a mere 230 miles away!
In 1958, Australia and New Zealand issued a stamp to commemorate the 30th Anniversary of the first air crossing of the Tasman Sea. Both stamps showed Charles Kingsford-Smith's aircraft, "Southern Cross".
Emblazoned on the side is the code VH-USU. However, that code wan't added to the aircraft until 1931. When the flight took place, the aircraft's code was G-AUSU.