event- spells not always doing damage even with new book in hand

[flappy6]

I dunno if this was intended,but I casted wither earthquake and thunderstorm with the new crafted book in my hand and it only damaged some targets...kept testing,casted explode flamestrike and only one spell did damage...
if that's intended that's just crazy hard to do that spawn

 

[Khyro]

Which wave were you on? There are 4 types of Skelementals, each 100% immune to all elemental types except one (in addition to 95%) physical resist.

The waves are designed to have you use a variety of spells and not just spam a single aoe like last year.

 

[flappy6]

I had 122 spell damage increase casting wither, thunderstorm, earthquake, meteor swarm in wraith form and it was taking forever ,they must have way too many hp
That was first level