diff --git a/addons/project/models/project.py b/addons/project/models/project.py
index cf2e784a455..988d70842f6 100644
--- a/addons/project/models/project.py
+++ b/addons/project/models/project.py
@@ -116,8 +116,14 @@ class Project(models.Model):
             ])
 
     def _compute_task_count(self):
-        task_data = self.env['project.task'].read_group(['|', '&', ('stage_id.is_closed', '=', False), ('stage_id.fold', '=', False), ('stage_id', '=', False)],
-                                                        ['project_id', 'display_project_id:count'], ['project_id'])
+        task_data = self.env['project.task'].read_group(
+            [('project_id', 'in', self.ids),
+             '|',
+                '&',
+                ('stage_id.is_closed', '=', False),
+                ('stage_id.fold', '=', False),
+             ('stage_id', '=', False)],
+            ['project_id', 'display_project_id:count'], ['project_id'])
         result_wo_subtask = defaultdict(int)
         result_with_subtasks = defaultdict(int)
         for data in task_data: