POE2 0.4.0 BUG Report: Armour -> Elemental Damage Tooltip/Modifer Bugged?

I am looking at a piece of gear, and I was curious to find out, if an Armour% on a necklace would increase the Damage output on the modifier

"+x% Armour also applies to Elemental Damage" -

I see that when I equip the armor with this mod, the base damage values in the tool-tips increase for about 1 second - then reset back as if this Modifier wasn't on the gear at all.

Further more, when I equipped an amulet with +x% Increased Armour - the tool-tip for the damage on all the spells sky rocket - and then again. Reset.

I don't know if the tool-tip is bugged, or if the actual Modifier is bugged.

Which would this lead to --- "Hayoxi's Soul Core of Heatproofing" to also being bugged as well?

I'm scared to put this resource into my helmet, if the overall "Armour-> Ele Damage (or Cold Damage)" isn't working properly.