>>45786792You know what else was inconsistent?
- Moves being Physical or Special on a per-type basis instead of per-move basis until that suddenly changed in Gen 3
- Several Pokemon gaining a brand new Fairy-type or having one of their old types replaced with it in gen 6
- The Rotom appliances suddenly switching from all being Electric/Ghost to Electric/Whatever the type of the move that appliance learns is.
- Feebas evolving with a held item instead of with max beauty after Gen 4 starting with Gen 5
- The abilities Drizzle, Drought, Sand Stream, and Snow Warning suddenly not causing infinite weather starting with Gen 5.
They definitely aren't 100% locked into being consistent between gens at all times, if these could happen I see no reason why a Pokemon could not be able to use Eviolite one gen and then be able to use it the next.