1 files changed, 6 insertions, 0 deletions
diff --git a/core/API/DataTablePostProcessor.php b/core/API/DataTablePostProcessor.php
index c2fdd1569c..c4eb7441d0 100644
--- a/core/API/DataTablePostProcessor.php
+++ b/core/API/DataTablePostProcessor.php
@@ -170,6 +170,12 @@ class DataTablePostProcessor
     public function applyFlattener($dataTable)
     {
         if (Common::getRequestVar('flat', '0', 'string', $this->request) == '1') {
+            // skip flattening if not supported by report and remove subtables only
+            if ($this->report && !$this->report->supportsFlatten()) {
+                $dataTable->filter('RemoveSubtables');
+                return $dataTable;
+            }
+
             $flattener = new Flattener($this->apiModule, $this->apiMethod, $this->request);
             if (Common::getRequestVar('include_aggregate_rows', '0', 'string', $this->request) == '1') {
                 $flattener->includeAggregateRows();