reverted:
--- b/core/includes/install.core.inc
+++ a/core/includes/install.core.inc
@@ -6,7 +6,6 @@
  */
 
 use Drupal\Component\Utility\UrlHelper;
-use Drupal\Core\Cache\Cache;
 use Drupal\Core\DrupalKernel;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Database\DatabaseExceptionWrapper;
@@ -157,7 +156,6 @@
       install_display_output($output, $state);
     }
     elseif ($state['installation_finished']) {
-      // Cache::getBins()['config']->delete('last_write_timestamp_cache_config');
       // Redirect to the newly installed site.
       install_goto('');
     }
diff -u b/core/lib/Drupal/Core/Cache/ChainedFastBackend.php b/core/lib/Drupal/Core/Cache/ChainedFastBackend.php
--- b/core/lib/Drupal/Core/Cache/ChainedFastBackend.php
+++ b/core/lib/Drupal/Core/Cache/ChainedFastBackend.php
@@ -149,7 +149,7 @@
       // are potentially invalid if older than the last time the bin was
       // written to in the consistent backend, so only keep ones that aren't.
       foreach ($items as $item) {
-        if ($item->created < $last_write_timestamp) {
+        if ($item->created <= $last_write_timestamp) {
           $cids[array_search($item->cid, $cids_copy)] = $item->cid;
         }
         else {
@@ -300,7 +300,7 @@
     // millisecond are invalidated. It is possible that caches will be later in
     // the same millisecond and are then incorrectly invalidated, but that only
     // costs one additional roundtrip to the persistent cache.
-    $now = round(microtime(TRUE) + .001, 4);
+    $now = round(microtime(TRUE) + .001, 3);
     if ($now > $this->getLastWriteTimestamp()) {
       $this->lastWriteTimestamp = $now;
       $this->consistentBackend->set(self::LAST_WRITE_TIMESTAMP_PREFIX . $this->bin, $this->lastWriteTimestamp);