Lightning elemental damage

I find that the lightning element seems to do May more damage than any others at the moment. I have a build focusing on poison dmg which includes affixes with 20% extra poison damage etc. I also have prismatic so sometimes when using skull shield it pops up as being a lightning skull shield. Now here I’d where I find it slightly odd that if I’m doing poison damage with my skull shield I’m getting crits of around 8 million. But if I’m doing lightning damage I’m doing around 14 million crits.

I’m sure I’m missing something very obvious here but I have affixes 3 x 20% poison dmg so why does it do less damage than lightning? Many thanks.

Elements can be “effective” against other elements. Fire vs Ice monsters and vice versa, same goes for poison and shock. Were you fighting against poison monsters? Or maybe they had poison resist.

I also have the legend affix ignore resist. It seems to be the same for any monster type.

Lightning got debuff stack up to 4 times, it make the monster receive more damage each stack