diff --git a/lib/Parser/MimeDir.php b/lib/Parser/MimeDir.php
index ea5ac0326..9b36df6a9 100644
--- a/lib/Parser/MimeDir.php
+++ b/lib/Parser/MimeDir.php
@@ -378,7 +378,7 @@ protected function readProperty($line)
                     $property['parameters'][$lastParam] = $value;
                 } elseif (is_array($property['parameters'][$lastParam])) {
                     $property['parameters'][$lastParam][] = $value;
-                } else {
+                } elseif ($property['parameters'][$lastParam] !== $value) {
                     $property['parameters'][$lastParam] = [
                         $property['parameters'][$lastParam],
                         $value,
diff --git a/tests/VObject/ReaderTest.php b/tests/VObject/ReaderTest.php
index 0992806be..63d1dccf2 100644
--- a/tests/VObject/ReaderTest.php
+++ b/tests/VObject/ReaderTest.php
@@ -450,4 +450,28 @@ public function testReadXMLStream()
         $this->assertEquals('VCALENDAR', $result->name);
         $this->assertEquals(0, count($result->children()));
     }
+
+    public function testReadDuplicateValue()
+    {
+        $input = <<<ICS
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Proton Technologies//ProtonCalendar Beta//EN
+CALSCALE:GREGORIAN
+METHOD:PUBLISH
+BEGIN:VEVENT
+DTSTAMP:20210903T154413Z
+DTSTART;VALUE=DATE;VALUE=DATE:20210818
+DTEND;VALUE=DATE;VALUE=DATE:20210819
+SUMMARY:test
+UID:62c73pe43p2oqci37q4g2pu580@google.com
+LOCATION:home
+END:VEVENT
+END:VCALENDAR
+ICS;
+
+        $result = Reader::read($input);
+        $expected = "DTSTART;VALUE=DATE:20210818\r\n";
+        $this->assertSame($expected, $result->VEVENT->DTSTART->serialize());
+    }
 }