Foulborn Skin of the Lords Changing Life Total

I have a foulborn skin with MoM and increased resistance. When I equip the item my life goes from 7614 to 7270 (changing no chest piece to equipped piece). A double foulborn (quality and increased res) does not change my life total. Note I tested other keystones and same result for single foulborn increased res.

Edit: solved MoM has a life tag