diff --git a/classes/deck/nodes/math/vector_subtract.gd b/classes/deck/nodes/math/vector_subtract.gd
index 347a137..700a231 100644
--- a/classes/deck/nodes/math/vector_subtract.gd
+++ b/classes/deck/nodes/math/vector_subtract.gd
@@ -25,21 +25,24 @@ func _init() -> void:
 
 func _receive(port : int, data : Variant) -> void:
 	
-	var va = data
-	if !DeckType.is_valid_vector(data):
-		
-		DeckHolder.logger.log_node("Vector Sub: Port %d: Supplied data was not a valid Vector.  Please ensure it is a Dictionary with keys 'x' and 'y'" % port)
-		return
-	
+	var va
 	var vb
+	
 	if port == 0:
+		va = data
 		
 		vb = await request_value_async(1)
 		
 	else:
 		
-		vb = await request_value_async(0)
+		va = await request_value_async(0)
 		
+		vb = data
+	
+	if (not DeckType.is_valid_vector(va)) or (not DeckType.is_valid_vector(vb)):
+		DeckHolder.logger.log_node("Vector Sub: Port %d: one of the inputs is not a valid Vector. Please ensure it is a Dictionary with keys 'x' and 'y'." % port)
+		return
+	
 	
 	var calc = subtract_vectors(va, vb)