Index: ps/trunk/binaries/data/mods/public/gui/session/session.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/session.js
+++ ps/trunk/binaries/data/mods/public/gui/session/session.js
@@ -483,6 +483,8 @@
 	updateGameSpeedControl();
 
 	// Update GUI and clear player-dependent cache
+	g_TemplateData = {};
+	Engine.GuiInterfaceCall("ResetTemplateModified");
 	onSimulationUpdate();
 
 	if (g_IsDiplomacyOpen)
@@ -783,10 +785,14 @@
 
 function onSimulationUpdate()
 {
-	// Templates change depending on technologies and auras, so they have to be reloaded every turn.
+	// Templates change depending on technologies and auras, so they have to be reloaded after such a change.
 	// g_TechnologyData data never changes, so it shouldn't be deleted.
 	g_EntityStates = {};
-	g_TemplateData = {};
+	if (Engine.GuiInterfaceCall("IsTemplateModified"))
+	{
+		g_TemplateData = {};
+		Engine.GuiInterfaceCall("ResetTemplateModified");
+	}
 	g_SimState = undefined;
 
 	if (!GetSimState())
Index: ps/trunk/binaries/data/mods/public/simulation/components/GuiInterface.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/components/GuiInterface.js
+++ ps/trunk/binaries/data/mods/public/simulation/components/GuiInterface.js
@@ -34,6 +34,7 @@
 	this.entsRallyPointsDisplayed = [];
 	this.entsWithAuraAndStatusBars = new Set();
 	this.enabledVisualRangeOverlayTypes = {};
+	this.templateModified = {};
 };
 
 /*
@@ -634,6 +635,25 @@
 };
 
 /**
+ * State of the templateData (player dependent): true when some template values have been modified
+ * and need to be reloaded by the gui.
+ */
+GuiInterface.prototype.OnTemplateModification = function(msg)
+{
+	this.templateModified[msg.player] = true;
+};
+
+GuiInterface.prototype.IsTemplateModified = function(player)
+{
+	return this.templateModified[player] || false;
+};
+
+GuiInterface.prototype.ResetTemplateModified = function()
+{
+	this.templateModified = {};
+};
+
+/**
  * Add a timed notification.
  * Warning: timed notifacations are serialised
  * (to also display them on saved games or after a rejoin)
@@ -1919,6 +1939,8 @@
 
 	"GetTraderNumber": 1,
 	"GetTradingGoods": 1,
+	"IsTemplateModified": 1,
+	"ResetTemplateModified": 1
 };
 
 GuiInterface.prototype.ScriptCall = function(player, name, args)