Devs, please make job crystals in lv 31+ content mandatory.

[Jeeqbit]

I think that this is very rare. I've done nearly 10,000 dungeons, trials and raids and not seen it done intentionally.

Even if it happens, it only affects the potency of their attacks. The gear is what really matters for calculating the base damage that this potency uses and the gear should be intact whether a stone is equipped or not. It's going to be akin to someone doing their rotation poorly.