diff --git a/addons/project_issue/models/project_issue.py b/addons/project_issue/models/project_issue.py
index e63d3b16f28..2eec0b49aa6 100644
--- a/addons/project_issue/models/project_issue.py
+++ b/addons/project_issue/models/project_issue.py
@@ -133,7 +133,7 @@ class ProjectIssue(models.Model):
     def _onchange_task_id(self):
         self.user_id = self.task_id.user_id
 
-    @api.one
+    @api.multi
     def copy(self, default=None):
         if default is None:
             default = {}