I thought that the Magisterium is infallible. According to
Catholicism.org: Vatican I taught that “both the Extraordinary (or Solemn) magisterium and the ordinary and universal magisterium are instruments of transmitting infallible dogma”:
*Wherefore, by divine and catholic faith all those things are to be believed which are contained in the word of God as found in scripture and tradition, and which are proposed by the church as matters to be believed as divinely revealed, whether by her solemn judgment or in her ordinary and universal magisterium.*8]
“This passage tells us that the Church’s magisterium is infallible in both its solemn and its ordinary and universal modes.”
catholicism.org/the-three-levels-of-magisterial-teaching.html
So if the Magisterium is infallible, how could it make the error you mention? And if the Magisterium is not infallible, then what other of its teachings are also in error?