Merge pull request #11387 from Heroman3003/dupefix

Fixes infinite material duplication in R&D

code/game/objects/items/stacks/stack.dm

@@ -79,7 +79,7 @@
 
 /obj/item/stack/tgui_data(mob/user, datum/tgui/ui, datum/tgui_state/state)
 	var/list/data = ..()
-	
+
 	data["amount"] = get_amount()
 
 	return data
@@ -123,7 +123,7 @@
 			if(get_amount() < 1)
 				qdel(src)
 				return
-			
+
 			var/datum/stack_recipe/R = locate(params["ref"])
 			if(!is_valid_recipe(R, recipes)) //href exploit protection
 				return FALSE
@@ -302,6 +302,7 @@
 	if(uses_charge)
 		return null
 
+	tamount = round(tamount)
 	var/transfer = max(min(tamount, src.amount, initial(max_amount)), 0)
 
 	var/orig_amount = src.amount