The advancement "How Did We Get Here?", by definition, requires the player to have every survival-obtainable effect applied at the same time. However, from 1.12 on it's possible to be inflicted with Blindness from the Illusioner mob, which isn't required for the effect.
This could be intentional as to not make the advancement impossible to achieve, as Illusioners are a tricky mob to handle. Though a similar case happened with the Resistance effect during the 1.12 development cycle, which later got added to the list (see [MC-117341]).
This might be since Illusioners currently don't spawn in-game and don't have a spawn egg, and requiring Blindness would make the advancement unable to be completed in Survival.