Aftershock stacks weirdly with other % armor increase + Iron skin/Mirror Shell bugs

Aftershock Tried it with iron skin and with poppy w. I was always 20+ or 20- off. I said 20- 20+ because i tried all the formulas i could think of.

Iron skin + poppy w works fine but aftershock doesn't. I know how formulas work because i managed to calculate chogath+gargoyle+cinderhulk pre bug fix (yea that was hard)

Iron skin/Mirror Shell Iron skin currently increases base armor. Don't know if that's intended since all the other % increase don't and neither Mirror Shell. These ones also don't increase their respective resistance when you use a Kleptomancy potion.