if you suspect the staff crossup at any point (jcable normal, IAD, j.2d; she can do it from 5b, 5a and 2a), you can punish it only if you jump back before the first hit, its not air unblockable. what will happen is you will ib the first hit and the second hit (the low) will whiff, giving you enough time to punish with 5b for big damage.
definitely try to always do this on reaction. on block the crossup is +19, and on hit it leads to big damage.
l havent tested what would happen if she rc's the first hit, or if there are other ways out of this (i'm thinking late as possible 2c, or dash forward, perhaps even late backdash or td with meter). i'll be testing