Yulsaria's Glacier has a custom Crystal Nova effect, sound and animation. The animation does not work when combining it with the White Sentry immortal weapon.

The White Sentry is supposed to have a copy of every animation, since the item requires that, due to its moving parts (altough I don't get why it was done this way, instead of animating the staff itself, like how it was done for e.g. Elder Titan's immortal). But the item is missing an animation for the Glacier immortal.

These are the Crystal Nova animations her default model has:

1. nova_anim (default)
2. cm_immortal_nova (Yulsaria's Glacier)
3. ward_nova_anim (White Sentry's copy of default)

So she is missing:

1. ward_immortal_nova (White Sentry copy of Yulsaria's Glacier).

Same goes for her arcana. Her arcana model has absolutely no Yulsaria's Glacier Cyrystal Nova animation.

These are the Crystal Nova animations her arcana model has:

1. arcana_nova_anim (arcana default)
2. wardstaff_arcana_nova_anim (White Sentry copy of arcana default)

So she is missing:

1. arcana_immortal_nova_anim (Yulsaria's Glacier + arcana)
2. wardstaff_arcana_immortal_nova_anim (White Sentry copy of Yulsaria's Glacier + arcana copy)