Update project_task.py

custom_project/models/project_task.py

@@ -45,10 +45,18 @@ class ProjectTask(models.Model):
     def onchange_start_date(self):
         for rec in self:
             if rec.x_start_date:
-                rec.planned_date_begin = datetime.combine(rec.x_start_date, datetime.min.time()) + timedelta(hours=15)
+                rec.planned_date_begin = datetime.combine(rec.x_start_date, datetime.min.time()) + timedelta(hours=9)
 
     @api.onchange("x_end_date")
     def onchange_end_date(self):
         for rec in self:
             if rec.x_end_date:
-                rec.date_deadline = datetime.combine(rec.x_end_date, datetime.min.time()) + timedelta(hours=24)
+                rec.date_deadline = datetime.combine(rec.x_end_date, datetime.min.time()) + timedelta(hours=9)
+
+    def write(self, vals):
+        if vals and type(vals) == dict:
+            if vals.get("x_start_date") or vals.get("x_end_date"):
+                for rec in self:
+                    rec.planned_date_begin = datetime.combine(rec.x_start_date, datetime.min.time()) + timedelta(hours=9)
+                    rec.date_deadline = datetime.combine(rec.x_end_date, datetime.min.time()) + timedelta(hours=9)
+        return super().write(vals)