Index: html/typo3/sysext/core/Classes/Service/FlexFormService.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/html/typo3/sysext/core/Classes/Service/FlexFormService.php b/html/typo3/sysext/core/Classes/Service/FlexFormService.php
--- a/html/typo3/sysext/core/Classes/Service/FlexFormService.php	(date 1631283839296)
+++ b/html/typo3/sysext/core/Classes/Service/FlexFormService.php	(date 1631283839296)
@@ -84,7 +84,7 @@
                     return $nodeValue;
                 }
                 if (in_array($nodeKey, ['el', '_arrayContainer'])) {
-                    return $this->walkFlexFormNode($nodeValue, $valuePointer);
+                    return empty($nodeValue) ? [] : $this->walkFlexFormNode($nodeValue, $valuePointer);
                 }
                 if (($nodeKey[0] ?? '') === '_') {
                     continue;