diff -u b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
--- b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
@@ -532,7 +532,7 @@
       $this->assertCount(0, $cache_items);
     }
     else {
-      $this->assertNotEmpty($cache_items);
+      $this->assertLessThanOrEqual(2, count($cache_items));
       $found_cached_200_response = FALSE;
       $other_cached_responses_are_4xx = TRUE;
       foreach ($cache_items as $cache_item) {