diff --git a/src/PhpSpreadsheet/Reader/Xlsx.php b/src/PhpSpreadsheet/Reader/Xlsx.php
index 8ae685037b..db4a34c4b4 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx.php
@@ -940,7 +940,10 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
                                     }
                                     $node->addAttribute('sqref', $item->children(Namespaces::DATA_VALIDATIONS2)->sqref);
                                     if (isset($item->formula1)) {
-                                        $node->addChild('formula1', $item->formula1->children(Namespaces::DATA_VALIDATIONS2)->f);
+                                        $childNode = $node->addChild('formula1');
+                                        if ($childNode !== null) { // null should never happen
+                                            $childNode[0] = (string) $item->formula1->children(Namespaces::DATA_VALIDATIONS2)->f; // @phpstan-ignore-line
+                                        }
                                     }
                                 }
                             }
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3145Test.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3145Test.php
new file mode 100644
index 0000000000..b7d3a4cc71
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3145Test.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
+
+use PhpOffice\PhpSpreadsheet\IOFactory;
+use PHPUnit\Framework\TestCase;
+
+class Issue3145Test extends TestCase
+{
+    public function testIssue3145(): void
+    {
+        $filename = 'tests/data/Reader/XLSX/issue.3145.xlsx';
+        $reader = IOFactory::createReader('Xlsx');
+        $spreadsheet = $reader->load($filename);
+        $sheet = $spreadsheet->getActiveSheet();
+
+        self::assertEquals('Headline A', $sheet->getCell('A1')->getValue());
+        self::assertEquals('Configdential B', $sheet->getCell('A2')->getValue());
+        self::assertSame('OFFSET(INDIRECT(SUBSTITUTE($A2," ","")),0,0,COUNTA(INDIRECT(SUBSTITUTE($A2," ","")&"Col")),1)', $sheet->getCell('B2')->getDataValidation()->getFormula1());
+
+        $spreadsheet->disconnectWorksheets();
+    }
+}
diff --git a/tests/data/Reader/XLSX/issue.3145.xlsx b/tests/data/Reader/XLSX/issue.3145.xlsx
new file mode 100644
index 0000000000..9fd3646245
Binary files /dev/null and b/tests/data/Reader/XLSX/issue.3145.xlsx differ