herald of ice bug?

herald of ice has 3 abilities.
deal x-y cold damage (aoe)
add x-y cold damage to spell.
add x-y cold damage to attack.
herald of ice has written is a spell.

add x-y cold damage to spell or attack. cold damage is elemental damage right. why does cold damage not increase with my gear and also passive skill tree? the gear has increase elemental damage.
it is a spell, right. I have passive tree increase spell damage, my wand has increase spell damage. but I don't see add x-y cold damage (to spell, to attack) increase.

finally.
the first ability.
heral of ice is a spell, right. ( sorry I don't see it)
my passive skill tree has 102 increase spell damage, and 16 increase elemental damage with spell. it also has 70 increase elemental damage , 18 increase cold damage.
my heral of ice is level 19. first ability deal 129-193. I look at cold damage, it's only 243-263 cold damage. that only equal 70% increase elemental damage +18% increase cold damage. it doesn't add my 16% increase elemental damage with the spell, also 102 increase spell damage. I haven't include my wand and my shield yet.

I'm having a hard time following all the numbers you threw out there. Where are you looking at the Herald of Ice numbers? On the gem, on your default attack tooltip, on the Herald of Ice tooltip, or on the skill that you're using's tooltip?

It should add to your damage the same way it would if you had flat damage on your gear. I don't think spell damage would increase it separately from the spell you are casting. Otherwise you'd get the increased spell damage added in twice, once for the HoI and once for the spell you are casting. I think you need to look at the tooltip of the spell you are casting, not of the HoI.

Herald of Ice is a spell meaning you cast it as a spell when you activate it just the same way as for example the Anger aura. That doesn't mean it necessarily adds spell damage but rather adds damage to both direct damage spells and attacks that you use.
I assume that you are using a wand to attack so the added damage from HoI is also considered attack damage. This again means that it will profit from any increase to generic elemental, cold and weapon elemental damage you have.
If you were using a spell to attack instead then you would also get the spell damage bonus counted in. Just try it out and slap on any random lvl 1 spellgem with 100% damage effectivness like for example Fireball. You will notice that you get more extra damage compared to your wand attack from it because of your extra spell damage increase. Also make sure to count in any damage effectivness your skill has for added damage.

[TL;DR]: using HoI with
a) a wand attack (Power Siphon, Barrage, ...): elemental damage, cold damage, weapon elemental damage, generic wand damage are counted
b) a spell: elemental damage, cold damage, spell damage are counted

For herald gems, the add dmg support gems (add cold, fire, lightning, chaos) only work for the 'explosion' part. This is because herald gems already act as additional 'add dmg' support gem for your UNLINKED attack/spell. i.e herald gems do not need to be linked to the skill gem in order to activate the extra dmg from herald.


So, if they allowed support gems to work with herald, you could essentially have 11 support gems for 1 atk/spell. 2 6-links. That'd be OP.