diff --git a/src/PhpSpreadsheet/Reader/Xlsx.php b/src/PhpSpreadsheet/Reader/Xlsx.php
index 4f7fbaaae..3a76b05b5 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx.php
@@ -945,6 +945,10 @@ class Xlsx extends BaseReader
                                                 // no style index means 0, it seems
                                                 $cell->setXfIndex(isset($styles[(int) ($cAttr['s'])]) ?
                                                     (int) ($cAttr['s']) : 0);
+                                                // issue 3495
+                                                if ($cell->getDataType() === DataType::TYPE_FORMULA) {
+                                                    $cell->getStyle()->setQuotePrefix(false);
+                                                }
                                             }
                                         }
                                         ++$rowIndex;
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3464Test.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3464Test.php
index f08af4863..90a34f3d5 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3464Test.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3464Test.php
@@ -18,7 +18,8 @@ class Issue3464Test extends \PHPUnit\Framework\TestCase
         $objReader = IOFactory::createReader($inputFileType);
         $objReader->setReadEmptyCells(false);
 
-        $sheet = $objReader->load(self::$testbook)->getActiveSheet();
+        $spreadsheet = $objReader->load(self::$testbook);
+        $sheet = $spreadsheet->getActiveSheet();
         $rickText = $sheet->getCell([1, 1])->getValue();
         self::assertInstanceOf(RichText::class, $rickText);
 
@@ -34,5 +35,6 @@ class Issue3464Test extends \PHPUnit\Framework\TestCase
         $font = $elements[1]->getFont();
         self::assertNotNull($font);
         self::assertEquals('ff2600', $font->getColor()->getRGB());
+        $spreadsheet->disconnectWorksheets();
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3495Test.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3495Test.php
new file mode 100644
index 000000000..b85d27e11
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3495Test.php
@@ -0,0 +1,57 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
+
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx;
+
+class Issue3495Test extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var string
+     */
+    private static $testbook = 'tests/data/Reader/XLSX/issue.3495d.xlsx';
+
+    public function testPreliminaries(): void
+    {
+        $file = 'zip://';
+        $file .= self::$testbook;
+        $file2 = $file;
+        $file .= '#xl/styles.xml';
+        $file2 .= '#xl/worksheets/sheet1.xml';
+        $data = file_get_contents($file);
+        if ($data === false) {
+            self::fail('Unable to read file');
+        } else {
+            // default style plus one other style
+            self::assertStringContainsString(
+                '<cellXfs count="2">'
+                . '<xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0"/>'
+                . '<xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0" quotePrefix="1"/>',
+                $data
+            );
+        }
+        $data = file_get_contents($file2);
+        if ($data === false) {
+            self::fail('Unable to read file');
+        } else {
+            // cells B1, C1, D1 all nominally use quotePrefix s="1"
+            self::assertStringContainsString('<c r="B1" s="1">', $data);
+            self::assertStringContainsString('<c r="C1" s="1" t="s">', $data);
+            self::assertStringContainsString('<c r="D1" s="1" t="s">', $data);
+        }
+    }
+
+    public function testFormulaDespiteQuotePrefix(): void
+    {
+        $reader = new Xlsx();
+        $spreadsheet = $reader->load(self::$testbook);
+        $sheet = $spreadsheet->getActiveSheet();
+        self::assertSame('=2+3', $sheet->getCell('B1')->getValue());
+        self::assertSame('=1+2', $sheet->getCell('C1')->getValue());
+        self::assertSame('3', $sheet->getCell('D1')->getValue());
+        self::assertSame(5, $sheet->getCell('B1')->getCalculatedValue());
+        self::assertSame('=1+2', $sheet->getCell('C1')->getCalculatedValue());
+        self::assertSame('3', $sheet->getCell('D1')->getCalculatedValue());
+        $spreadsheet->disconnectWorksheets();
+    }
+}
diff --git a/tests/data/Reader/XLSX/issue.3495d.xlsx b/tests/data/Reader/XLSX/issue.3495d.xlsx
new file mode 100644
index 000000000..ac5c2e7cb
Binary files /dev/null and b/tests/data/Reader/XLSX/issue.3495d.xlsx differ