Is Knightfall Supposed to Unlock at Level 20?

The in-game Knightfall Graphic recommends level 20+. Every other AB recommends (requires) level 75+ and is geared in difficulty towards level 85, if we're honest. 

Is this just a typo and only players level 75+ can see the event? Or did someone flip the wrong switch and new players are about to get really frustrated by an event they can't do or what is going on here?