diff --git a/addons/website_event_sale/controllers/main.py b/addons/website_event_sale/controllers/main.py
index 900b0b66c7b..839653ab0ac 100644
--- a/addons/website_event_sale/controllers/main.py
+++ b/addons/website_event_sale/controllers/main.py
@@ -55,6 +55,8 @@ class WebsiteEventSaleController(WebsiteEventController):
                 data['sale_order_id'] = order_sudo.id
                 data['sale_order_line_id'] = cart_data[event_ticket_id]
 
+        request.session['website_sale_cart_quantity'] = order_sudo.cart_quantity
+
         return super()._create_attendees_from_registration_post(event, registration_data)
 
     @route()
diff --git a/addons/website_sale/controllers/main.py b/addons/website_sale/controllers/main.py
index c5ac062db80..e0ffebeac10 100644
--- a/addons/website_sale/controllers/main.py
+++ b/addons/website_sale/controllers/main.py
@@ -499,6 +499,9 @@ class WebsiteSale(http.Controller):
         if order and order.state != 'draft':
             request.session['sale_order_id'] = None
             order = request.website.sale_get_order()
+
+        request.session['website_sale_cart_quantity'] = order.cart_quantity
+
         values = {}
         if access_token:
             abandoned_order = request.env['sale.order'].sudo().search([('access_token', '=', access_token)], limit=1)
@@ -557,6 +560,8 @@ class WebsiteSale(http.Controller):
             **kwargs
         )
 
+        request.session['website_sale_cart_quantity'] = sale_order.cart_quantity
+
         if express:
             return request.redirect("/shop/checkout?express=1")
 
@@ -597,6 +602,8 @@ class WebsiteSale(http.Controller):
             **kw
         )
 
+        request.session['website_sale_cart_quantity'] = order.cart_quantity
+
         if not order.cart_quantity:
             request.website.sale_reset()
             return values
@@ -627,8 +634,9 @@ class WebsiteSale(http.Controller):
 
     @http.route(['/shop/cart/quantity'], type='json', auth="public", methods=['POST'], website=True, csrf=False)
     def cart_quantity(self):
-        cart = request.website.sale_get_order()
-        return cart and cart.cart_quantity or 0
+        if 'website_sale_cart_quantity' not in request.session:
+            return request.website.sale_get_order().cart_quantity
+        return request.session['website_sale_cart_quantity']
 
     # ------------------------------------------------------
     # Checkout
diff --git a/addons/website_sale/models/sale_order.py b/addons/website_sale/models/sale_order.py
index 1954e9f761f..0ea76a2402a 100644
--- a/addons/website_sale/models/sale_order.py
+++ b/addons/website_sale/models/sale_order.py
@@ -124,7 +124,8 @@ class SaleOrder(models.Model):
         self = self.with_company(self.company_id)
 
         if self.state != 'draft':
-            request.session['sale_order_id'] = None
+            request.session.pop('sale_order_id', None)
+            request.session.pop('website_sale_cart_quantity', None)
             raise UserError(_('It is forbidden to modify a sales order which is not in draft status.'))
 
         product = self.env['product.product'].browse(product_id).exists()
diff --git a/addons/website_sale/models/website.py b/addons/website_sale/models/website.py
index 152676765be..e82cce92018 100644
--- a/addons/website_sale/models/website.py
+++ b/addons/website_sale/models/website.py
@@ -302,7 +302,8 @@ class Website(models.Model):
         if not (sale_order_sudo or force_create):
             # Do not create a SO record unless needed
             if request.session.get('sale_order_id'):
-                request.session['sale_order_id'] = None
+                request.session.pop('sale_order_id')
+                request.session.pop('website_sale_cart_quantity', None)
             return self.env['sale.order']
 
         # Only set when neeeded
@@ -316,6 +317,7 @@ class Website(models.Model):
             sale_order_sudo = SaleOrder.with_user(SUPERUSER_ID).create(so_data)
 
             request.session['sale_order_id'] = sale_order_sudo.id
+            request.session['website_sale_cart_quantity'] = sale_order_sudo.cart_quantity
             # The order was created with SUPERUSER_ID, revert back to request user.
             sale_order_sudo = sale_order_sudo.with_user(self.env.user).sudo()
             return sale_order_sudo
@@ -327,6 +329,7 @@ class Website(models.Model):
         # case when user emptied the cart
         if not request.session.get('sale_order_id'):
             request.session['sale_order_id'] = sale_order_sudo.id
+            request.session['website_sale_cart_quantity'] = sale_order_sudo.cart_quantity
 
         # check for change of partner_id ie after signup
         if sale_order_sudo.partner_id.id != partner_sudo.id and request.website.partner_id.id != partner_sudo.id:
@@ -435,10 +438,9 @@ class Website(models.Model):
         return fpos.id
 
     def sale_reset(self):
-        request.session.update({
-            'sale_order_id': False,
-            'website_sale_current_pl': False,
-        })
+        request.session.pop('sale_order_id', None)
+        request.session.pop('website_sale_current_pl', None)
+        request.session.pop('website_sale_cart_quantity', None)
 
     @api.model
     def action_dashboard_redirect(self):
diff --git a/addons/website_sale/views/templates.xml b/addons/website_sale/views/templates.xml
index 3041b31f2d7..31a8af23e08 100644
--- a/addons/website_sale/views/templates.xml
+++ b/addons/website_sale/views/templates.xml
@@ -5,14 +5,14 @@
            t-nocache-_icon="_icon"
            t-nocache-_item_class="_item_class"
            t-nocache-_link_class="_link_class">
-            <t t-set="website_sale_order" t-value="website.sale_get_order()" />
+            <t t-set="website_sale_cart_quantity" t-value="request.session['website_sale_cart_quantity'] if 'website_sale_cart_quantity' in request.session else website.sale_get_order().cart_quantity or 0"/>
             <t t-set="show_cart" t-value="true"/>
             <li t-attf-class="#{_item_class} divider d-none"/> <!-- Make sure the cart and related menus are not folded (see autohideMenu) -->
             <li t-attf-class="o_wsale_my_cart align-self-md-start #{not show_cart and 'd-none'} #{_item_class}">
                 <a href="/shop/cart" t-attf-class="#{_link_class}">
                     <i t-if="_icon" class="fa fa-shopping-cart"/>
                     <span t-if="_text">My Cart</span>
-                    <sup class="my_cart_quantity badge badge-primary" t-esc="website_sale_order and website_sale_order.cart_quantity or '0'" t-att-data-order-id="website_sale_order and website_sale_order.id or ''"/>
+                    <sup class="my_cart_quantity badge badge-primary" t-esc="website_sale_cart_quantity" t-att-data-order-id="request.session.get('sale_order_id', '')"/>
                 </a>
             </li>
         </t>
@@ -20,7 +20,7 @@
 
     <template id="header_hide_empty_cart_link" inherit_id="website_sale.header_cart_link" name="Header Hide Empty Cart link" active="False">
         <xpath expr="//t[@t-set='show_cart']" position="after">
-            <t t-set="show_cart" t-value="show_cart and website_sale_order and website_sale_order.cart_quantity" />
+            <t t-set="show_cart" t-value="website_sale_cart_quantity" />
         </xpath>
     </template>
 
diff --git a/addons/website_sale_product_configurator/controllers/main.py b/addons/website_sale_product_configurator/controllers/main.py
index 11c7db05a1f..c3966a88ca5 100644
--- a/addons/website_sale_product_configurator/controllers/main.py
+++ b/addons/website_sale_product_configurator/controllers/main.py
@@ -96,4 +96,6 @@ class WebsiteSale(main.WebsiteSale):
                     )
                     option_parent[option['unique_id']] = option_value['line_id']
 
+        request.session['website_sale_cart_quantity'] = order.cart_quantity
+
         return str(order.cart_quantity)
diff --git a/addons/website_sale_wishlist/static/src/js/website_sale_wishlist.js b/addons/website_sale_wishlist/static/src/js/website_sale_wishlist.js
index 832a421581f..e441f18e6c4 100644
--- a/addons/website_sale_wishlist/static/src/js/website_sale_wishlist.js
+++ b/addons/website_sale_wishlist/static/src/js/website_sale_wishlist.js
@@ -191,6 +191,7 @@ publicWidget.registry.ProductWishlist = publicWidget.Widget.extend(VariantMixin,
                 var cart_alert = $('.wishlist-section').parent().find('#data_warning');
                 cart_alert.html('<button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button> ' + resp.warning);
             }
+            sessionStorage.setItem('website_sale_cart_quantity', resp.cart_quantity);
             $('.my_cart_quantity').html(resp.cart_quantity || '<i class="fa fa-warning" /> ');
         });
     },