diff --git a/dbcon/mysql/ha_window_function.cpp b/dbcon/mysql/ha_window_function.cpp
index c53b0094c..1ad45583c 100755
--- a/dbcon/mysql/ha_window_function.cpp
+++ b/dbcon/mysql/ha_window_function.cpp
@@ -680,6 +680,7 @@ ReturnedColumn* buildWindowFunctionColumn(Item* item, gp_walk_info& gwi, bool& n
 				break;
 			case Item_sum::UDF_SUM_FUNC:
 			{
+				// UDAnF functions each have their own default set in context.
 				mcsv1sdk::mcsv1Context& context = ac->getUDAFContext();
 				if (context.getRunFlag(UDAF_WINDOWFRAME_REQUIRED))
 				{
diff --git a/utils/rowgroup/rowaggregation.cpp b/utils/rowgroup/rowaggregation.cpp
index f12f0d811..b0f239329 100755
--- a/utils/rowgroup/rowaggregation.cpp
+++ b/utils/rowgroup/rowaggregation.cpp
@@ -792,6 +792,14 @@ void RowAggregation::initialize()
 	{
 		fRowGroupOut->setRowCount(1);
 		attachGroupConcatAg();
+		// For UDAF, reset the data
+		for (uint64_t i = 0; i < fFunctionCols.size(); i++)
+		{
+			if (fFunctionCols[i]->fAggFunction == ROWAGG_UDAF)
+			{
+				resetUDAF(i);
+			}
+		}
 	}