The "prophecy" was discovered more than four centuries after St. Malachy's death.
Many consider it to be a forgery for two reasons:
1. The popes prior to the discovery fit very well into the predictions. The popes after the discovery require a lot of latitude to fit within the predictions.
2. Some of the prophecies only apply to anti-popes.
I totally agree. Calling John XXIII a navigator? Calling Benedict, ‘the glory of the olives’ because he chose ‘Benedict’ as a name?