POE2 resistance question

So I completed all the permanent res upgrades in normal mode, and I just completed the cold res upgrade in act 1 cruel.

I notice that out in an area, as opposed to town, my res is 10 percent higher for fire cold and lightning. Why is this? What drops my res in town? At first I thought maybe it didn't count the perma bonus in town, but then you'd think I'd see 20 percent fall off for cold since I have 20 percent bonus for that?

Someone please just help me understand what I'm seeing here.

Thanks