diff --git a/bug/operation.go b/bug/operation.go
index 08d44d0cc0f29118019ce6b806b24f7b6ef37950..f42a1192321e0e1b88c5ce8600934a114413b9c4 100644
--- a/bug/operation.go
+++ b/bug/operation.go
@@ -137,6 +137,7 @@ func (op *OpBase) SetMetadata(key string, value string) {
 	}
 
 	op.Metadata[key] = value
+	op.hash = ""
 }
 
 // GetMetadata retrieve arbitrary metadata about the operation