diff --git a/src/CodeCoverage.php b/src/CodeCoverage.php
index bdf9c64c3..ba4f1f8c3 100644
--- a/src/CodeCoverage.php
+++ b/src/CodeCoverage.php
@@ -150,6 +150,14 @@ public function clear(): void
         $this->cachedReport = null;
     }
 
+    /**
+     * @internal
+     */
+    public function clearCache(): void
+    {
+        $this->cachedReport = null;
+    }
+
     /**
      * Returns the filter object used.
      */
diff --git a/src/Report/PHP.php b/src/Report/PHP.php
index 2058fb39a..1f8186d04 100644
--- a/src/Report/PHP.php
+++ b/src/Report/PHP.php
@@ -21,6 +21,8 @@ final class PHP
 {
     public function process(CodeCoverage $coverage, ?string $target = null): string
     {
+        $coverage->clearCache();
+
         $buffer = "<?php
 return \unserialize(<<<'END_OF_COVERAGE_SERIALIZATION'" . PHP_EOL . serialize($coverage) . PHP_EOL . 'END_OF_COVERAGE_SERIALIZATION' . PHP_EOL . ');';
 
diff --git a/tests/tests/Report/PhpTest.php b/tests/tests/Report/PhpTest.php
index 657278bcd..75c11b4ba 100644
--- a/tests/tests/Report/PhpTest.php
+++ b/tests/tests/Report/PhpTest.php
@@ -9,6 +9,7 @@
  */
 namespace SebastianBergmann\CodeCoverage\Report;
 
+use ReflectionProperty;
 use SebastianBergmann\CodeCoverage\TestCase;
 
 final class PhpTest extends TestCase
@@ -43,4 +44,22 @@ public function testPHPSerialisationProducesValidCodeWhenOutputIncludesSingleQuo
 
         $this->assertEquals($coverage, $unserialized);
     }
+
+    public function testCacheDataNeverGetSaved(): void
+    {
+        $coverage = $this->getLineCoverageForBankAccount();
+
+        // Warm up cache
+        $coverage->getReport();
+
+        $refProperty = new ReflectionProperty($coverage, 'cachedReport');
+        $refProperty->setAccessible(true);
+
+        $this->assertNotNull($refProperty->getValue($coverage));
+
+        /* @noinspection UnusedFunctionResultInspection */
+        (new PHP)->process($coverage, self::$TEST_TMP_PATH . '/serialized.php');
+
+        $this->assertNull($refProperty->getValue($coverage));
+    }
 }