diff --git a/core/operation.lisp b/core/operation.lisp
index 58d151b..4dc7531 100644
--- a/core/operation.lisp
+++ b/core/operation.lisp
@@ -92,7 +92,7 @@
:property property
:host (current-host)
:os os))
- (push op operations)))
+ (pushnew (the operation op) operations)))
(nreverse operations)))
(defgeneric resource-op-properties (resource))