Mastering the Foul Invoker of Varshan in Diablo 4's Malignant Echo Fight

In Diablo 4's Season of the Malignant, players encounter a problem with the Invoker of Varshan, needed to fight the Echo of Varshan. If on World Tier 3, the Invoker will not work, and players must scale back down to World Tier 1 or 2, redo the process, and craft a Foul Invoker using a regular Varshan Invoker and Sigil Dust. This unlocks the ability to fight Varshan on World Tier 3, but the fight is much harder. The game does not make this clear, and it seems like an oversight.