diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 841ff7f14bb4f98276293c1c5df1b97678eafb68..93295d4cee62697ffe14530ab6577688568f7607 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -610,7 +610,6 @@ default:
 
 '⚡️ PHPUnit Unit tests on PHP 8.5':
   <<: [ *default-job-settings-lint, *default-phpunit-job-settings ]
-  allow_failure: true
   variables:
     TESTSUITE: PHPUnit-Unit
     KUBERNETES_CPU_REQUEST: "4"
@@ -630,7 +629,6 @@ default:
 
 '⚡️ Component unit tests on PHP 8.5':
   <<: [ *default-job-settings-lint, *default-component-unit-test-job-settings ]
-  allow_failure: true
   variables:
     KUBERNETES_CPU_REQUEST: "2"
     _TARGET_PHP: "8.5-ubuntu"
diff --git a/core/modules/migrate/src/Plugin/migrate/process/StaticMap.php b/core/modules/migrate/src/Plugin/migrate/process/StaticMap.php
index 152603098ffdb9e416457aa52098b71272a2f460..768320a63c95512f5c5507537b5ecf68dfba6fde 100644
--- a/core/modules/migrate/src/Plugin/migrate/process/StaticMap.php
+++ b/core/modules/migrate/src/Plugin/migrate/process/StaticMap.php
@@ -113,18 +113,6 @@
  *       'TRUE': to
  * @endcode
  *
- * A NULL can be mapped. If the value of the source property 'foo' is NULL then
- * the value of the destination property bar will be 'to'.
- *
- * @code
- * process:
- *   bar:
- *     plugin: static_map
- *     source: foo
- *     map:
- *       NULL: to
- * @endcode
- *
  * If your source data contains booleans, the boolean is treated as a numeric 0
  * or 1. If the value of the source property 'foo' is TRUE then the value of the
  * destination property bar will be 'bar'. And if the value of the source
@@ -141,6 +129,10 @@
  *       1: bar
  * @endcode
  *
+ * Note you cannot map NULL to a value. Use the default_value or bypass setting
+ * instead. If you need to differentiate between NULL and empty strings,
+ * then use the bypass setting and a custom process plugin.
+ *
  * @see https://www.drupal.org/project/drupal/issues/2827897
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  */
@@ -151,6 +143,25 @@ class StaticMap extends ProcessPluginBase {
    * {@inheritdoc}
    */
   public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    if ($value === NULL) {
+      if (array_key_exists('', $this->configuration['map'])) {
+        if (array_key_exists('default_value', $this->configuration) && $this->configuration['default_value'] === $this->configuration['map']['']) {
+          return $this->configuration['default_value'];
+        }
+        @trigger_error('Relying on mapping NULL values via an empty string map key in ' . __CLASS__ . '::transform() is deprecated in drupal:11.3.0 and will trigger a Drupal\migrate\MigrateSkipRowException from drupal:12.0.0. Set the empty string map value as the "default_value" in the plugin configuration. See https://www.drupal.org/node/3557003', E_USER_DEPRECATED);
+        // Preserve the current behavior of returning the value mapped to an
+        // empty string for NULL.
+        return $this->configuration['map'][''];
+      }
+      if (array_key_exists('default_value', $this->configuration)) {
+        return $this->configuration['default_value'];
+      }
+      if (!empty($this->configuration['bypass'])) {
+        return NULL;
+      }
+      throw new MigrateSkipRowException(sprintf("No static mapping possible for NULL and no default value provided for destination '%s'.", $destination_property));
+    }
+
     $new_value = $value;
     if (is_array($value)) {
       if (!$value) {
diff --git a/core/modules/migrate/tests/src/Unit/process/StaticMapTest.php b/core/modules/migrate/tests/src/Unit/process/StaticMapTest.php
index 45e1f0d6511d1d4ac333e2f970ecace885806716..5a14238159b00c33a4876079bb25559acbeaf41e 100644
--- a/core/modules/migrate/tests/src/Unit/process/StaticMapTest.php
+++ b/core/modules/migrate/tests/src/Unit/process/StaticMapTest.php
@@ -9,6 +9,7 @@
 use Drupal\migrate\MigrateSkipRowException;
 use Drupal\migrate\Plugin\migrate\process\StaticMap;
 use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\IgnoreDeprecations;
 
 /**
  * Tests the static map process plugin.
@@ -98,21 +99,56 @@ public function testMapWithInvalidSourceAndBypass(): void {
    */
   public function testWithNullSourceNotInMap(): void {
     $this->expectException(MigrateSkipRowException::class);
-    $this->expectExceptionMessage("No static mapping found for 'NULL' and no default value provided for destination 'destination_property'");
+    $this->expectExceptionMessage("No static mapping possible for NULL and no default value provided for destination 'destination_property'");
     $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destination_property');
   }
 
   /**
-   * Tests when the source is invalid but there's a default.
+   * Tests when the source is invalid but there's a mapping via an empty string.
    */
-  public function testWithNullSource(): void {
+  #[IgnoreDeprecations]
+  public function testWithNullSourceWithEmptyStringMapping(): void {
     $configuration['map']['foo']['bar'] = 'baz';
-    $configuration['map'][NULL] = 'mapped NULL';
+    $configuration['map'][''] = 'mapped NULL';
     $this->plugin = new StaticMap($configuration, 'map', []);
+    $this->expectDeprecation('Relying on mapping NULL values via an empty string map key in Drupal\migrate\Plugin\migrate\process\StaticMap::transform() is deprecated in drupal:11.3.0 and will trigger a Drupal\migrate\MigrateSkipRowException from drupal:12.0.0. Set the empty string map value as the "default_value" in the plugin configuration. See https://www.drupal.org/node/3557003');
     $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destination_property');
     $this->assertSame('mapped NULL', $value);
   }
 
+  /**
+   * Tests when the source is invalid but bypass is set to TRUE.
+   */
+  public function testWithNullSourceBypass(): void {
+    $configuration['map']['foo']['bar'] = 'baz';
+    $configuration['bypass'] = TRUE;
+    $this->plugin = new StaticMap($configuration, 'map', []);
+    $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destination_property');
+    $this->assertNull($value);
+  }
+
+  /**
+   * Tests when the source is invalid but default_value is set to TRUE.
+   */
+  public function testWithNullSourceDefaultValue(): void {
+    $configuration['map']['foo']['bar'] = 'baz';
+    $configuration['default_value'] = FALSE;
+    $this->plugin = new StaticMap($configuration, 'map', []);
+    $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destination_property');
+    $this->assertFalse($value);
+  }
+
+  /**
+   * Tests when the source returns an empty string and it is mapped to a value.
+   */
+  public function testWithEmptyStringMap(): void {
+    $configuration['map']['foo']['bar'] = 'baz';
+    $configuration['map'][''] = 'mapped empty string';
+    $this->plugin = new StaticMap($configuration, 'map', []);
+    $value = $this->plugin->transform('', $this->migrateExecutable, $this->row, 'destination_property');
+    $this->assertSame('mapped empty string', $value);
+  }
+
   /**
    * Tests when there is a dot in a map key.
    */