you can confirm the dmg type with DPYes [Tool] DPYes - Player/pet DPS meter & Misc util
if it’s not just a weird tooltip display (which tbh to me sounds new), could be a new interaction related to FX change/priority system? or the modifier just isnt’ applied right?
edit
quick try, i get the same tooltip error when equipping both, but atleast DPYes says dmg is non pierce
i’d probably move this to bug report for the tooltip
*as far as the actual dmg type, slot priority seems like it’s not being applied and the conversion is split, dealing majority lightning/3x as much lightining as fire/cold on my setup - unsure if the flat mods on helmet is just that heavy to make that big difference or from getting 66% converted to lightning
edit, just realize, slot priority isn’t a factor here, it’s only a factor when converting ele → X, not X → ele, so 66% conversion is expected