diff --git a/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala b/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala
index 1c0f7bbf7..cd0b830b2 100644
--- a/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala
+++ b/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala
@@ -295,6 +295,7 @@ class CometSparkSessionExtensions
             case Some(nativeOp) =>
               val cometOp = CometUnionExec(u, u.children)
               CometSinkPlaceHolder(nativeOp, u, cometOp)
+            case None => u
           }
 
         case op =>
diff --git a/spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala b/spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala
index 609026ee0..e52018b38 100644
--- a/spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala
+++ b/spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala
@@ -1698,6 +1698,10 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
 
         if (scanTypes.length == op.output.length) {
           scanBuilder.addAllFields(scanTypes.asJava)
+
+          // Sink operators don't have children
+          result.clearChildren()
+
           Some(result.setScan(scanBuilder).build())
         } else {
           // There are unsupported scan type