Say for instance I have different gear with different elemental damage types on it. 4 poison, 3 fire, 3 cold. Should each hit get an extra 10 damage split out into those 3 types? What I am currently seeing is that only the highest is getting counted, so in the above case, I am only seeing a max of 4 poison damage added.

Also, interestingly "Thorns" damage is being counted twice, once as Damage Shield Damage, and then again as Fire Damage.

Nah, it adds up but only shows the dominant color. Imagine how awful it would be to show 5 different elemental popups. That's why I did that.

I'll look change the fire shield damage to be thorns. It's really a thorn attack, not really an elemental one.

Just checked. Shield of Lava gets lumped in with all other thorn damage, so not sure what you're seeing.