I’ve moved this to bug reports because it sounds like something fishy is going on. Can you post the skill you are using along with and image of how it is spec’d or upload the save itself? I’d like to try and reproduce it.
So, it looks like all the mods are melee cold damage. Only 1/3 of Tempest Strike is cold damage. The base flat damage it deals is 1 cold, 1 physical and 1 lightning. So you need a lot of flat added melee cold damage if you want to scale the cold portion of this hit with increased melee cold damage.
The triggered abilities that happen with it are considered spells so increased melee cold damage doesn’t actually help them at all.
Skills do not gain damage strictly from level. They only gain damage if you put points into nodes which gain damage.
Tempest Strike is also just not very good in general right now.
I’m thinking that there isn’t actually any bug happening now but I’m not entirely certain.
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