diff --git a/CRM/Report/Form/Activity.php b/CRM/Report/Form/Activity.php
index ed95a7722c04..cdaf918dfa06 100644
--- a/CRM/Report/Form/Activity.php
+++ b/CRM/Report/Form/Activity.php
@@ -542,7 +542,7 @@ public function where($recordType = NULL) {
           }
           else {
             $op = $this->_params["{$fieldName}_op"] ?? NULL;
-            if ($op && !($fieldName == "contact_{$recordType}" && ($op != 'nnll' || $op != 'nll'))) {
+            if ($op && !($fieldName === "contact_{$recordType}" && ($op === 'nnll' || $op === 'nll'))) {
               $clause = $this->whereClause($field,
                 $op,
                 CRM_Utils_Array::value("{$fieldName}_value", $this->_params),
diff --git a/tests/phpunit/api/v3/ReportTemplateTest.php b/tests/phpunit/api/v3/ReportTemplateTest.php
index 6316cde92e82..94bb75e412d8 100644
--- a/tests/phpunit/api/v3/ReportTemplateTest.php
+++ b/tests/phpunit/api/v3/ReportTemplateTest.php
@@ -1259,6 +1259,23 @@ public function testActivityDetailsNullFilters() {
     $this->assertEmpty($rowsWithNullTarget);
   }
 
+  /**
+   * Test the source contact filter works.
+   *
+   * @throws \CRM_Core_Exception
+   */
+  public function testActivityDetailsContactFilter() {
+    $this->createContactsWithActivities();
+    $params = [
+      'report_id' => 'activity',
+      'contact_source_op' => 'has',
+      'contact_source_value' => 'z',
+      'options' => ['metadata' => ['sql']],
+    ];
+    $rows = $this->callAPISuccess('report_template', 'getrows', $params);
+    $this->assertContains("civicrm_contact_source.sort_name LIKE '%z%'", $rows['metadata']['sql'][3]);
+  }
+
   /**
    * Set up some activity data..... use some chars that challenge our utf handling.
    */