diff --git a/app/bundles/CoreBundle/Helper/UrlHelper.php b/app/bundles/CoreBundle/Helper/UrlHelper.php
index 6b5fffb05dd..c323dbf493a 100644
--- a/app/bundles/CoreBundle/Helper/UrlHelper.php
+++ b/app/bundles/CoreBundle/Helper/UrlHelper.php
@@ -179,7 +179,7 @@ public static function getUrlsFromPlaintext($text, array $contactUrlFields = [])
 
             // We don't want to match URLs in token default values
             // like {contactfield=website|http://ignore.this.url}
-            if (preg_match_all("#{(.*?)\|".preg_quote($url).'}#', $text, $matches)) {
+            if (preg_match_all("/{(.*?)\|".preg_quote($url, '/').'}/', $text, $matches)) {
                 unset($urls[$key]);
 
                 // We know this is a URL due to the default so let's include it as a trackable
diff --git a/app/bundles/CoreBundle/Tests/unit/Helper/UrlHelperTest.php b/app/bundles/CoreBundle/Tests/unit/Helper/UrlHelperTest.php
index a728e9c1fb3..fba8cdcec6e 100644
--- a/app/bundles/CoreBundle/Tests/unit/Helper/UrlHelperTest.php
+++ b/app/bundles/CoreBundle/Tests/unit/Helper/UrlHelperTest.php
@@ -124,6 +124,7 @@ public function testGetUrlsFromPlaintextWithSymbols()
                 'https://example.org/with/query?utm_campaign=hello',
                 'https://example.org/with/tokenized-query?foo={contactfield=bar}&bar=foo',
                 'https://example.org/with/just-tokenized-query?foo={contactfield=bar}',
+                'https://example.org/with/query?utm_campaign=_hello#_underscore-test',
             ],
             UrlHelper::getUrlsFromPlaintext(
                 <<<STRING
@@ -143,6 +144,7 @@ public function testGetUrlsFromPlaintextWithSymbols()
 Checkout my UTM tags https://example.org/with/query?utm_campaign=hello.
 Hey what about https://example.org/with/tokenized-query?foo={contactfield=bar}&bar=foo.
 What happens with this https://example.org/with/just-tokenized-query?foo={contactfield=bar}?
+Underscore test https://example.org/with/query?utm_campaign=_hello#_underscore-test
 STRING
             )
         );