diff -u b/core/modules/update/tests/src/Unit/ProjectCoreCompatibilityTest.php b/core/modules/update/tests/src/Unit/ProjectCoreCompatibilityTest.php
--- b/core/modules/update/tests/src/Unit/ProjectCoreCompatibilityTest.php
+++ b/core/modules/update/tests/src/Unit/ProjectCoreCompatibilityTest.php
@@ -20,10 +20,12 @@
     $project_compatibility = new ProjectCoreCompatibility($core_data, $core_releases);
     $project_compatibility->setStringTranslation($this->getStringTranslationStub());
     $project_compatibility->setReleaseMessage($project_data);
-    // Ignore the <details> markup, and only assert that the core compatibility
-    // constraint, range message and core compatible boolean matches.
+    // Ignore the <details> markup and 'hide_download_link' flag so we only
+    // assert that the core compatibility constraint, range message and core
+    // compatible boolean matches.
     $purge_compatibility_details = function ($release) {
       unset($release['core_compatibility_details']);
+      unset($release['hide_download_link']);
       return $release;
     };
     $project_data['releases'] = array_map($purge_compatibility_details, $project_data['releases']);