diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6f130519..9b9deca8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased]
+
+### Fixed
+
+- Fix mandatory fields of a block hidden by its display conditions blocking the save of an item
+
 ## [1.25.0] - 2026-10-06
 
 ### Added
diff --git a/inc/container.class.php b/inc/container.class.php
index 2c023504..e94d1752 100644
--- a/inc/container.class.php
+++ b/inc/container.class.php
@@ -2215,6 +2215,12 @@ private static function checkContainerMandatory(CommonDBTM $item, PluginFieldsCo
             return [];
         }
 
+        //container hidden by its display conditions: its fields can't be filled
+        $display_condition = new PluginFieldsContainerDisplayCondition();
+        if (!$display_condition->computeDisplayContainer($item, $c_id)) {
+            return [];
+        }
+
         $status_field_name = PluginFieldsStatusOverride::getStatusFieldName($item::class);
         $data = ['plugin_fields_containers_id' => $c_id];
         if ($item->input['_auto_import'] ?? false) {
diff --git a/inc/field.class.php b/inc/field.class.php
index fcca8817..9144f8cb 100644
--- a/inc/field.class.php
+++ b/inc/field.class.php
@@ -1349,7 +1349,7 @@ public static function prepareHtmlFields(
                 $value = is_array($decoded) ? $decoded : [];
             }
 
-            if ($field['multiple'] && is_array($value)) {
+            if ($field['multiple']) {
                 // Flatten any nested arrays caused by corrupted DB data (double-encoded values)
                 // so that Dropdown::show() always receives a flat list of scalars.
                 $value = array_values(array_filter(
diff --git a/tests/Units/ContainerItemUpdateTest.php b/tests/Units/ContainerItemUpdateTest.php
index 3809d60e..9152d69b 100644
--- a/tests/Units/ContainerItemUpdateTest.php
+++ b/tests/Units/ContainerItemUpdateTest.php
@@ -35,6 +35,7 @@
 use Glpi\Tests\GLPITestCase;
 use GlpiPlugin\Field\Tests\FieldTestTrait;
 use PluginFieldsContainer;
+use PluginFieldsContainerDisplayCondition;
 use Ticket;
 use Entity;
 use Notification;
@@ -1037,4 +1038,76 @@ public function testSuccessiveUpdatesOverwritePluginFieldValues(): void
             'Plugin value must not be erased by a native-only update.',
         );
     }
+
+    /**
+     * A mandatory DOM field must not block creation/update when its container is
+     * hidden by a display condition.
+     */
+    public function testNotBlockedWhenMandatoryDomContainerIsHidden(): void
+    {
+        $this->login();
+
+        $container = $this->createFieldContainer([
+            'label'        => 'Hidden Mandatory Dom Container',
+            'type'         => 'dom',
+            'itemtypes'    => [Ticket::class],
+            'is_active'    => 1,
+            'entities_id'  => 0,
+            'is_recursive' => 1,
+        ]);
+        $this->createField([
+            'label'                                     => 'Mandatory Field',
+            'type'                                      => 'text',
+            PluginFieldsContainer::getForeignKeyField() => $container->getID(),
+            'ranking'                                   => 1,
+            'is_active'                                 => 1,
+            'is_readonly'                               => 0,
+            'mandatory'                                 => 1,
+        ]);
+
+        // Hide the container for incidents.
+        $this->createItem(PluginFieldsContainerDisplayCondition::class, [
+            PluginFieldsContainer::getForeignKeyField() => $container->getID(),
+            'itemtype'                                  => Ticket::class,
+            'search_option'                             => 14, // type
+            'condition'                                 => PluginFieldsContainerDisplayCondition::SHOW_CONDITION_EQ,
+            'value'                                     => Ticket::INCIDENT_TYPE,
+        ]);
+
+        // The container is visible for requests
+        $ticket = new Ticket();
+        $ticket_id = $ticket->add([
+            'name'        => 'Request with visible mandatory field',
+            'content'     => 'Test',
+            'entities_id' => 0,
+            'type'        => Ticket::DEMAND_TYPE,
+        ]);
+        $this->assertFalse($ticket_id, 'A mandatory field in a visible container must block creation.');
+        $this->hasSessionMessageThatContains(
+            __('Some mandatory fields are empty', 'fields'),
+            ERROR,
+        );
+        $this->hasSessionMessageThatContains(
+            __('The form or source creating this item does not provide the mandatory fields above: map them to it, or make them optional.', 'fields'),
+            ERROR,
+        );
+
+        $ticket = new Ticket();
+        $ticket = $this->createItem(Ticket::class, [
+            'name'        => 'Incident with hidden mandatory field',
+            'content'     => 'Test',
+            'entities_id' => 0,
+            'type'        => Ticket::INCIDENT_TYPE,
+        ]);
+
+        $is_updated = $ticket->update([
+            'id'   => $ticket->getID(),
+            'type' => Ticket::DEMAND_TYPE,
+        ]);
+        $this->assertFalse($is_updated);
+        $this->hasSessionMessageThatContains(
+            __('Some mandatory fields are empty', 'fields'),
+            ERROR,
+        );
+    }
 }
diff --git a/tests/Units/MassiveActionGlpiItemDropdownTest.php b/tests/Units/MassiveActionGlpiItemDropdownTest.php
index 12663d61..e77c164e 100644
--- a/tests/Units/MassiveActionGlpiItemDropdownTest.php
+++ b/tests/Units/MassiveActionGlpiItemDropdownTest.php
@@ -64,7 +64,7 @@ public function setUp(): void
 
     public function tearDown(): void
     {
-        unset($_REQUEST['massiveaction'], $_POST);
+        unset($_REQUEST['massiveaction']);
         $this->tearDownFieldTest();
         GLPITestCase::tearDown();
     }
diff --git a/tests/Units/MassiveActionRealFlowTest.php b/tests/Units/MassiveActionRealFlowTest.php
index 488809a2..1d373160 100644
--- a/tests/Units/MassiveActionRealFlowTest.php
+++ b/tests/Units/MassiveActionRealFlowTest.php
@@ -62,7 +62,7 @@ public function setUp(): void
 
     public function tearDown(): void
     {
-        unset($_REQUEST['massiveaction'], $_POST);
+        unset($_REQUEST['massiveaction']);
         $this->tearDownFieldTest();
         GLPITestCase::tearDown();
     }