diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index 4f882b877b1..3c9b822708c 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -4933,7 +4933,17 @@ WinGetSlotInFrame(WindowObject winobj, TupleTableSlot *slot,
 	if (isout)
 		*isout = false;
 	if (set_mark)
+	{
+		/*
+		 * If RPR is enabled and seek type is WINDOW_SEEK_TAIL, we set the
+		 * mark position unconditionally to frameheadpos. In this case the
+		 * frame always starts at CURRENT_ROW and never goes back, thus
+		 * setting the mark at the position is safe.
+		 */
+		if (winstate->rpPattern != NULL && seektype == WINDOW_SEEK_TAIL)
+			mark_pos = winstate->frameheadpos;
 		WinSetMarkPosition(winobj, mark_pos);
+	}
 	return 0;
 
 out_of_frame:
diff --git a/src/backend/utils/adt/windowfuncs.c b/src/backend/utils/adt/windowfuncs.c
index efb60c99052..74ef109f72e 100644
--- a/src/backend/utils/adt/windowfuncs.c
+++ b/src/backend/utils/adt/windowfuncs.c
@@ -682,7 +682,7 @@ window_last_value(PG_FUNCTION_ARGS)
 
 	WinCheckAndInitializeNullTreatment(winobj, true, fcinfo);
 	result = WinGetFuncArgInFrame(winobj, 0,
-								  0, WINDOW_SEEK_TAIL, false,
+								  0, WINDOW_SEEK_TAIL, true,
 								  &isnull, NULL);
 	if (isnull)
 		PG_RETURN_NULL();