diff --git a/Civi/DataProcessor/FilterHandler/ContactInGroupFilter.php b/Civi/DataProcessor/FilterHandler/ContactInGroupFilter.php
index cc5387a72d0fd71fe6f687317d9d7c4241e4f969..96a66ff75f5e195dadef0cf43c702f9430632935 100644
--- a/Civi/DataProcessor/FilterHandler/ContactInGroupFilter.php
+++ b/Civi/DataProcessor/FilterHandler/ContactInGroupFilter.php
@@ -68,7 +68,7 @@ class ContactInGroupFilter extends AbstractFieldFilterHandler {
         $groupFilters,
         $dataFlow->getName(),
         $this->inputFieldSpecification->name,
-        $filter['op']
+        'IN'
       );
 
       $dataFlow->addWhereClause($this->whereClause);