On the contrary, the reason it states it can be carried by a crystal wyvern could be due to a plethora of reasons, one being the due fact crystal wyverns do not yet exist on ASA without mods of some kind, which means it’s just a mere placeholder, and /or perhaps the dev thought it would be funny to put that there to make you ask about it

Another reason could be what if Crystal wyverns will be getting size variations that could make them bigger than regular wyverns, to mimic the fact real crystals can grow to impressive size, and/or it could just be a way to get your own crystal wyvern heir that looks the same as the Queen ( yes and the cool looking skull) but only slightly smaller which means still being the largest wyvern in the game able to pick up nearly anything in the game, which you can obtain by an egg after you kill the Queen, the egg may hatch to be any Color and the level depends on difficulty, just think of Fjordur and how Fenrirs work.