diff --git a/odex25_project/project_base/models/project_phase.py b/odex25_project/project_base/models/project_phase.py
index d5d551b2f..508611997 100644
--- a/odex25_project/project_base/models/project_phase.py
+++ b/odex25_project/project_base/models/project_phase.py
@@ -136,14 +136,21 @@ class ProjectPhase(models.Model):
                 progress =  ((sum([x.weight * x.task_progress for x in done_task]))  / 100)
                 # progress = round(100.0 * float((len(done_task) / len(rec.task_ids))), 2)
             rec.progress = progress
-            
+
     @api.constrains('start_date', 'end_date')
     def _check_dates(self):
         for rec in self:
-            if rec.filtered(lambda c: c.end_date and c.start_date > c.end_date):
+            if rec.start_date and rec.end_date and rec.start_date > rec.end_date:
                 raise ValidationError(_('Phase start date must be earlier than Phase end date.'))
-            if rec.project_id.start and rec.project_id.date and (rec.start_date < rec.project_id.start or rec.start_date > rec.project_id.date) or \
-               (rec.end_date < rec.project_id.start or rec.end_date > rec.project_id.date):
+
+            project = rec.project_id
+            if not project.start or not project.date:
+                continue
+
+            if rec.start_date and (rec.start_date < project.start or rec.start_date > project.date):
+                raise ValidationError(_('Phase dates must be between project dates.'))
+
+            if rec.end_date and (rec.end_date < project.start or rec.end_date > project.date):
                 raise ValidationError(_('Phase dates must be between project dates.'))
 
     def action_draft(self):