diff --git a/htdocs/reception/class/reception.class.php b/htdocs/reception/class/reception.class.php
index 34f3d736857..55072848b4a 100644
--- a/htdocs/reception/class/reception.class.php
+++ b/htdocs/reception/class/reception.class.php
@@ -827,8 +827,11 @@ class Reception extends CommonObject
 					if ((!getDolGlobalInt('STOCK_SUPPORTS_SERVICES') && $origin_line->product_type > 0) || $origin_line->product_type > 1) {
 						continue;
 					}
-
-					$qty_wished[$origin_line->fk_product] += $origin_line->qty;
+					if (array_key_exists($origin_line->fk_product, $qty_wished)) {
+						$qty_wished[$origin_line->fk_product] += $origin_line->qty;
+					} else {
+						$qty_wished[$origin_line->fk_product] = $origin_line->qty;
+					}
 				}
 
 				// compare array