diff --git a/addons/sale_timesheet/models/project.py b/addons/sale_timesheet/models/project.py
index b19c7a5e1ae..e01376ea872 100644
--- a/addons/sale_timesheet/models/project.py
+++ b/addons/sale_timesheet/models/project.py
@@ -49,6 +49,7 @@ class Project(models.Model):
         compute="_compute_timesheet_product_id", store=True, readonly=False,
         default=_default_timesheet_product_id)
     warning_employee_rate = fields.Boolean(compute='_compute_warning_employee_rate')
+    partner_id = fields.Many2one(compute='_compute_partner_id', store=True, readonly=False)
 
     @api.depends('sale_line_id', 'sale_line_employee_ids', 'allow_billable')
     def _compute_pricing_type(self):
@@ -137,6 +138,15 @@ class Project(models.Model):
         for project in self.filtered(lambda p: not p.project_overview):
             project.project_overview = project.allow_billable or project.allow_timesheets
 
+    @api.depends('sale_line_employee_ids.sale_line_id', 'sale_line_id')
+    def _compute_partner_id(self):
+        for project in self:
+            if project.partner_id:
+                continue
+            if project.allow_billable and project.allow_timesheets and project.pricing_type != 'task_rate':
+                sol = project.sale_line_id or project.sale_line_employee_ids.sale_line_id[:1]
+                project.partner_id = sol.order_partner_id
+
     @api.constrains('sale_line_id')
     def _check_sale_line_type(self):
         for project in self.filtered(lambda project: project.sale_line_id):
diff --git a/addons/sale_timesheet/models/project_sale_line_employee_map.py b/addons/sale_timesheet/models/project_sale_line_employee_map.py
index 4df0f5a5ccf..bcb55ffd2f6 100644
--- a/addons/sale_timesheet/models/project_sale_line_employee_map.py
+++ b/addons/sale_timesheet/models/project_sale_line_employee_map.py
@@ -26,9 +26,14 @@ class ProjectProductEmployeeMap(models.Model):
         ('uniqueness_employee', 'UNIQUE(project_id,employee_id)', 'An employee cannot be selected more than once in the mapping. Please remove duplicate(s) and try again.'),
     ]
 
-    @api.depends('project_id.partner_id')
+    @api.depends('partner_id')
     def _compute_sale_line_id(self):
-        self.filtered(lambda map_entry: map_entry.sale_line_id.order_partner_id != map_entry.project_id.partner_id).update({'sale_line_id': False})
+        self.filtered(
+            lambda map_entry:
+                map_entry.sale_line_id
+                and map_entry.partner_id
+                and map_entry.sale_line_id.order_partner_id.commercial_partner_id != map_entry.partner_id.commercial_partner_id
+        ).update({'sale_line_id': False})
 
     @api.depends('sale_line_id', 'sale_line_id.price_unit')
     def _compute_price_unit(self):
diff --git a/addons/sale_timesheet/views/project_task_views.xml b/addons/sale_timesheet/views/project_task_views.xml
index 57ec55aafd4..4d0a8cabd28 100644
--- a/addons/sale_timesheet/views/project_task_views.xml
+++ b/addons/sale_timesheet/views/project_task_views.xml
@@ -31,7 +31,6 @@
                     <field name="sale_line_employee_ids">
                         <tree editable="bottom">
                             <field name="company_id" invisible="1"/>
-                            <field name="project_id" invisible="1"/>
                             <field name="partner_id" invisible="1"/>
                             <field name="employee_id" options="{'no_create': True}"/>
                             <field name="sale_line_id" attrs="{'required': True}" options="{'no_create': True}"/>