Resistance penetration is capped at 70%

game/modules/tome/class/interface/Combat.lua

@@ -2248,7 +2248,7 @@ end
 function _M:combatGetResistPen(type, straight)
 	if not self.resists_pen then return 0 end
 	local pen = (self.resists_pen.all or 0) + (self.resists_pen[type] or 0)
-	if straight then return pen end
+	if straight then return math.min(pen, 70) end
 	local add = 0
 
 	if self.auto_highest_resists_pen and self.auto_highest_resists_pen[type] then
@@ -2267,7 +2267,7 @@ function _M:combatGetResistPen(type, straight)
 		add = add + t.getPenetration(self, t)
 	end
 
-	return pen + add
+	return math.min(pen + add, 70)
 end
 
 --- Returns the damage affinity

game/modules/tome/class/interface/TooltipsData.lua

@@ -478,10 +478,12 @@ TOOLTIP_RESISTS_PEN_ALL = [[#GOLD#Damage penetration: all#LAST#
 Reduces the amount of effective resistance of your foes to any damage you deal by this percent.
 If you have 50% penetration against a creature with 50% resistance it will have an effective resistance of 25%.
 This stacks with individual damage type penetrations.
+You can never have more than 70% penetration.
 ]]
 TOOLTIP_RESISTS_PEN = [[#GOLD#Damage penetration: specific#LAST#
 Reduces the effective resistance of your foes to all damage of this type you deal by this percent.
 If you have 50% penetration against a creature with 50% resistance it will have an effective resistance of 25%.
+You can never have more than 70% penetration.
 ]]
 TOOLTIP_FLAT_RESIST = [[#GOLD#Flat resistances#LAST#
 Reduces each hit of a certain damage type (or all) by this amount.