diff -u b/core/modules/update/update.report.inc b/core/modules/update/update.report.inc
--- b/core/modules/update/update.report.inc
+++ b/core/modules/update/update.report.inc
@@ -112,10 +112,10 @@
  */
 function template_preprocess_update_version(array &$variables) {
   $version = $variables['version'];
-  $core_compatible = !empty($version['core_compatible']);
   if (empty($version['core_compatibility_message'])) {
     return;
   }
+  $core_compatible = !empty($version['core_compatible']);
   $variables['core_compatibility_details'] = [
     '#type' => 'details',
     '#title' => $core_compatible ? t('Compatible') : t('Not compatible'),