I do not know if this is by design or only because no one thought about: Why do mining crystals do not work in mining missions?? Why is it impossible to mine e.g. Banidine (Veldspar counterpart) with Simple Asteroid Mining crystals (and so on…) ??
I’m not sure of the reasons, but I think CCP is maybe still trying to figure out how to make the new residue mechanics of the crystals work inside those sites without breaking the mining missions. It is one of the ‘loose ends’ not yet resolved by them as far as I can see.
Tying up “loose ends” is not a CCP strong point, never has been, probably never will be.
The missions can be done with t1 mining lazers as these have 0 residue effect
mining missions is one of those old legacy things in eve that has a simple solution up the rewards by 20-25% to make up for no t2 leave it as a t1 module ore call it good and its a game mechanic but i don’t see ccp doing anything about it in the near future if ever .