diff --git a/Classes/Handler/Render/XpathRenderHandler.php b/Classes/Handler/Render/XpathRenderHandler.php
index d68a41312..e15af003c 100644
--- a/Classes/Handler/Render/XpathRenderHandler.php
+++ b/Classes/Handler/Render/XpathRenderHandler.php
@@ -55,7 +55,7 @@ public function renderTemplate(TemplateConfiguration $templateConfiguration, arr
         return '';
     }
 
-    protected function processContainer($node, $mappingConfiguration, $processedValues, $containerType, $mappingType = 'inner')
+    protected function processContainer(\DOMNode $node, array $mappingConfiguration, array $processedValues, string $containerType, string $mappingType = 'inner')
     {
         switch ($containerType) {
             case 'repeatable':
@@ -159,6 +159,7 @@ protected function processValue($processingNode, $fieldName, array $mappingConfi
     protected function processValueInner(array $mappingConfiguration, \DOMNode $processingNode, array $processedValues, string $fieldName)
     {
         if (isset($mappingConfiguration['container']) && is_array($mappingConfiguration['container'])) {
+            $processedFieldValues = (is_array($processedValues[$fieldName]) ? $processedValues[$fieldName] : []);
             $this->processContainer($processingNode, $mappingConfiguration['container'], $processedValues[$fieldName], $mappingConfiguration['containerType'], 'inner');
             return;
         }
@@ -203,6 +204,7 @@ protected function processValueInner(array $mappingConfiguration, \DOMNode $proc
     protected function processValueOuter(array $mappingConfiguration, \DOMNode $processingNode, array $processedValues, string $fieldName): void
     {
         if (isset($mappingConfiguration['container']) && is_array($mappingConfiguration['container'])) {
+            $processedFieldValues = (is_array($processedValues[$fieldName]) ? $processedValues[$fieldName] : []);
             $this->processContainer($processingNode, $mappingConfiguration['container'], $processedValues[$fieldName], $mappingConfiguration['containerType'], 'outer');
             return;
         }