diff --git a/code/game/machinery/computer/orders/order_computer/order_computer.dm b/code/game/machinery/computer/orders/order_computer/order_computer.dm
index 92942add2ea..6efe9dde527 100644
--- a/code/game/machinery/computer/orders/order_computer/order_computer.dm
+++ b/code/game/machinery/computer/orders/order_computer/order_computer.dm
@@ -134,12 +134,19 @@ GLOBAL_LIST_EMPTY(order_console_products)
 	switch(action)
 		if("add_one")
 			var/datum/orderable_item/wanted_item = locate(params["target"]) in GLOB.order_console_products
-			grocery_list[wanted_item] += 1
+			if(grocery_list[wanted_item] >= 20)
+				return
+			else
+				grocery_list[wanted_item] += 1
 		if("remove_one")
 			var/datum/orderable_item/wanted_item = locate(params["target"]) in GLOB.order_console_products
 			if(!grocery_list[wanted_item])
 				return
-			grocery_list[wanted_item] -= 1
+			if(grocery_list[wanted_item] < 1)
+				grocery_list[wanted_item] = 0
+				return
+			else
+				grocery_list[wanted_item] -= 1
 			if(!grocery_list[wanted_item])
 				grocery_list -= wanted_item
 		if("cart_set")
diff --git a/code/game/machinery/limbgrower.dm b/code/game/machinery/limbgrower.dm
index e5576bdb267..75976f98be3 100644
--- a/code/game/machinery/limbgrower.dm
+++ b/code/game/machinery/limbgrower.dm
@@ -80,9 +80,9 @@
 
 	var/list/available_nodes = stored_research.researched_designs.Copy()
 	if(imported_designs.len)
-		available_nodes += imported_designs
+		available_nodes |= imported_designs
 	if(obj_flags & EMAGGED)
-		available_nodes += stored_research.hacked_designs
+		available_nodes |= stored_research.hacked_designs
 
 	for(var/design_id in available_nodes)
 		var/datum/design/limb_design = SSresearch.techweb_design_by_id(design_id)
@@ -291,4 +291,4 @@
 	for(var/id in SSresearch.techweb_designs)
 		var/datum/design/found_design = SSresearch.techweb_design_by_id(id)
 		if((found_design.build_type & LIMBGROWER) && !(RND_CATEGORY_HACKED in found_design.category))
-			imported_designs += found_design.id
+			imported_designs |= found_design.id