diff --git a/addons/website/tests/test_assets.py b/addons/website/tests/test_assets.py
index 2ff336a9cfe..35f31350aa8 100644
--- a/addons/website/tests/test_assets.py
+++ b/addons/website/tests/test_assets.py
@@ -100,6 +100,42 @@ class TestWebsiteAssets(odoo.tests.HttpCase):
         new_public_assets_links = re.findall(r'(/web/assets/\d+/\w{7}/web.assets_frontend\..+)"/>', page)
         self.assertEqual(new_admin_assets_links, new_public_assets_links, "t-cache should have been invalidated for public user too")
 
+    def test_invalid_unlink(self):
+        self.env['ir.attachment'].search([('url', '=like', '/web/assets/%')]).unlink()
+
+        asset_bundle_xmlid = 'web.assets_frontend'
+        website_default = self.env['website'].search([], limit=1)
+
+        code = b"document.body.dataset.hello = 'world';"
+        attach = self.env['ir.attachment'].create({
+            'name': 'EditorExtension.css',
+            'mimetype': 'text/css',
+            'raw': code,
+        })
+        custom_url = '/_custom/web/content/%s/%s' % (attach.id, attach.name)
+        attach.url = custom_url
+
+        self.env['ir.asset'].create({
+            'name': 'EditorExtension',
+            'bundle': asset_bundle_xmlid,
+            'path': custom_url,
+            'website_id': website_default.id,
+        })
+
+        website_bundle = self.env['ir.qweb']._get_asset_bundle(asset_bundle_xmlid, assets_params={'website_id': website_default.id})
+        self.assertIn(custom_url, [f['url'] for f in website_bundle.files])
+        base_website_css_version = website_bundle.get_version('css')
+
+        no_website_bundle = self.env['ir.qweb']._get_asset_bundle(asset_bundle_xmlid)
+        self.assertNotIn(custom_url, [f['url'] for f in no_website_bundle.files])
+        self.assertNotEqual(no_website_bundle.get_version('css'), base_website_css_version)
+
+        website_attach = website_bundle.css()
+        self.assertTrue(website_attach.exists())
+        no_website_bundle.css()
+        self.assertTrue(website_attach.exists(), 'attachment for website should still exist after generating attachment for no website')
+
+
 @odoo.tests.tagged('-at_install', 'post_install')
 class TestWebAssets(odoo.tests.HttpCase):
     def test_assets_url_validation(self):
diff --git a/odoo/addons/base/models/assetsbundle.py b/odoo/addons/base/models/assetsbundle.py
index 6f5d85bc9f4..e78e17533d4 100644
--- a/odoo/addons/base/models/assetsbundle.py
+++ b/odoo/addons/base/models/assetsbundle.py
@@ -150,7 +150,7 @@ class AssetsBundle(object):
             self._checksum_cache[asset_type] = hashlib.sha512(unique_descriptor.encode()).hexdigest()[:64]
         return self._checksum_cache[asset_type]
 
-    def get_asset_url(self, unique='%', extension='%', ignore_params=False):
+    def get_asset_url(self, unique=ANY_UNIQUE, extension='%', ignore_params=False):
         direction = '.rtl' if self.is_css(extension) and self.rtl else ''
         bundle_name = f"{self.name}{direction}.{extension}"
         return self.env['ir.asset']._get_asset_bundle_url(bundle_name, unique, self.assets_params, ignore_params)
@@ -264,6 +264,7 @@ class AssetsBundle(object):
                 }
                 attachment = self.env['ir.attachment'].with_user(SUPERUSER_ID).create(values)
                 attachment_id = attachment.id
+                self.clean_attachments(extension)
 
         return self.env['ir.attachment'].sudo().browse(attachment_id)
 
diff --git a/odoo/addons/test_assetsbundle/tests/test_assetsbundle.py b/odoo/addons/test_assetsbundle/tests/test_assetsbundle.py
index 665224c9f6a..4e49ba99abd 100644
--- a/odoo/addons/test_assetsbundle/tests/test_assetsbundle.py
+++ b/odoo/addons/test_assetsbundle/tests/test_assetsbundle.py
@@ -15,7 +15,7 @@ import base64
 import odoo
 from odoo import api, http
 from odoo.addons import __path__ as ADDONS_PATH
-from odoo.addons.base.models.assetsbundle import AssetsBundle
+from odoo.addons.base.models.assetsbundle import AssetsBundle, ANY_UNIQUE
 from odoo.addons.base.models.ir_asset import AssetPaths
 from odoo.addons.base.models.ir_attachment import IrAttachment
 from odoo.modules.module import get_manifest
@@ -147,7 +147,7 @@ class TestJavascriptAssetsBundle(FileTouchable):
         bundle = self.jsbundle_name if extension in ['js', 'min.js'] else self.cssbundle_name
         direction = '.rtl' if rtl else ''
         bundle_name = f"{bundle}{direction}.{extension}"
-        url = self.env['ir.asset']._get_asset_bundle_url(bundle_name, '%', {})
+        url = self.env['ir.asset']._get_asset_bundle_url(bundle_name, ANY_UNIQUE, {})
         domain = [('url', '=like', url)]
         return self.env['ir.attachment'].search(domain)