diff --git a/ql/src/java/org/apache/hadoop/hive/ql/parse/GenTezUtils.java b/ql/src/java/org/apache/hadoop/hive/ql/parse/GenTezUtils.java
index a2512500e37b..f2998fc1e921 100644
--- a/ql/src/java/org/apache/hadoop/hive/ql/parse/GenTezUtils.java
+++ b/ql/src/java/org/apache/hadoop/hive/ql/parse/GenTezUtils.java
@@ -401,6 +401,7 @@ public static void removeUnionOperators(GenTezProcContext context, BaseWork work
     operators.addAll(newRoots);
 
     Set<Operator<?>> seen = new HashSet<Operator<?>>();
+    Set<Operator<?>> removedParents = new HashSet<Operator<?>>();
 
     Set<FileStatus> fileStatusesToFetch = null;
     if(context.parseContext.getFetchTask() != null) {
@@ -468,7 +469,12 @@ public static void removeUnionOperators(GenTezProcContext context, BaseWork work
           // root operator is union (can happen in reducers)
           replacementMap.put(current, current.getChildOperators().get(0));
         } else {
-          parent.removeChildAndAdoptItsChildren(current);
+          // For complex queries, there is a UNION with the same parent.
+          // In that case, the parent UNION that has already been removed will not be removed.
+          if (!removedParents.contains(parent)) {
+            parent.removeChildAndAdoptItsChildren(current);
+            removedParents.add(parent);
+          }
           operators.remove(current);
         }
       }
diff --git a/ql/src/test/results/clientpositive/llap/cte_mat_10.q.out b/ql/src/test/results/clientpositive/llap/cte_mat_10.q.out
index 8262ba7c035a..c8f2752e7f46 100644
--- a/ql/src/test/results/clientpositive/llap/cte_mat_10.q.out
+++ b/ql/src/test/results/clientpositive/llap/cte_mat_10.q.out
@@ -138,14 +138,16 @@ STAGE PLANS:
                     expressions: concat('b2 <- ', id) (type: string)
                     outputColumnNames: _col0
                     Statistics: Num rows: 1 Data size: 184 Basic stats: COMPLETE Column stats: NONE
-                    File Output Operator
-                      compressed: false
+                    Union
                       Statistics: Num rows: 6 Data size: 1005 Basic stats: COMPLETE Column stats: PARTIAL
-                      table:
-                          input format: org.apache.hadoop.mapred.SequenceFileInputFormat
-                          output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
-                          serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
-            Execution mode: vectorized, llap
+                      File Output Operator
+                        compressed: false
+                        Statistics: Num rows: 6 Data size: 1005 Basic stats: COMPLETE Column stats: PARTIAL
+                        table:
+                            input format: org.apache.hadoop.mapred.SequenceFileInputFormat
+                            output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
+                            serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
+            Execution mode: llap
             LLAP IO: all inputs
         Map 4 
             Map Operator Tree:
@@ -229,14 +231,16 @@ STAGE PLANS:
                     expressions: concat('b2 <- ', id) (type: string)
                     outputColumnNames: _col0
                     Statistics: Num rows: 1 Data size: 184 Basic stats: COMPLETE Column stats: NONE
-                    File Output Operator
-                      compressed: false
+                    Union
                       Statistics: Num rows: 6 Data size: 1005 Basic stats: COMPLETE Column stats: PARTIAL
-                      table:
-                          input format: org.apache.hadoop.mapred.SequenceFileInputFormat
-                          output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
-                          serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
-            Execution mode: vectorized, llap
+                      File Output Operator
+                        compressed: false
+                        Statistics: Num rows: 6 Data size: 1005 Basic stats: COMPLETE Column stats: PARTIAL
+                        table:
+                            input format: org.apache.hadoop.mapred.SequenceFileInputFormat
+                            output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
+                            serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
+            Execution mode: llap
             LLAP IO: all inputs
         Union 5 
             Vertex: Union 5