diff --git a/addons/website/models/ir_qweb.py b/addons/website/models/ir_qweb.py
index d3483fcb1b4..e4e5d45b22f 100644
--- a/addons/website/models/ir_qweb.py
+++ b/addons/website/models/ir_qweb.py
@@ -7,6 +7,7 @@ from odoo import models
 from odoo.http import request
 from odoo.addons.base.models.assetsbundle import AssetsBundle
 from odoo.addons.http_routing.models.ir_http import url_for
+from odoo.osv import expression
 from odoo.addons.website.models import ir_http
 from odoo.tools import html_escape as escape
 
@@ -21,6 +22,11 @@ class AssetsBundleMultiWebsite(AssetsBundle):
         res = super(AssetsBundleMultiWebsite, self)._get_asset_url_values(id, unique, extra, name, sep, type)
         return res
 
+    def _get_assets_domain_for_already_processed_css(self, assets):
+        res = super(AssetsBundleMultiWebsite, self)._get_assets_domain_for_already_processed_css(assets)
+        current_website = self.env['website'].get_current_website(fallback=False)
+        res = expression.AND([res, current_website.website_domain()])
+        return res
 
 class QWeb(models.AbstractModel):
     """ QWeb object for rendering stuff in the website context """
diff --git a/odoo/addons/base/models/assetsbundle.py b/odoo/addons/base/models/assetsbundle.py
index 0a8131ac989..4ba5b446d67 100644
--- a/odoo/addons/base/models/assetsbundle.py
+++ b/odoo/addons/base/models/assetsbundle.py
@@ -370,6 +370,12 @@ class AssetsBundle(object):
             })("%s");
         """ % message.replace('"', '\\"').replace('\n', '
')
 
+    def _get_assets_domain_for_already_processed_css(self, assets):
+        """ Method to compute the attachments' domain to search the already process assets (css).
+        This method was created to be overridden.
+        """
+        return [('url', 'in', list(assets.keys()))]
+
     def is_css_preprocessed(self):
         preprocessed = True
         attachments = None
@@ -381,7 +387,7 @@ class AssetsBundle(object):
             outdated = False
             assets = dict((asset.html_url, asset) for asset in self.stylesheets if isinstance(asset, atype))
             if assets:
-                assets_domain = [('url', 'in', list(assets.keys()))]
+                assets_domain = self._get_assets_domain_for_already_processed_css(assets)
                 attachments = self.env['ir.attachment'].sudo().search(assets_domain)
                 for attachment in attachments:
                     asset = assets[attachment.url]
@@ -441,7 +447,7 @@ class AssetsBundle(object):
                         fname = os.path.basename(asset.url)
                         url = asset.html_url
                         with self.env.cr.savepoint():
-                            self.env['ir.attachment'].sudo().with_context(not_force_website_id=True).create(dict(
+                            self.env['ir.attachment'].sudo().create(dict(
                                 datas=base64.b64encode(asset.content.encode('utf8')),
                                 mimetype='text/css',
                                 type='binary',