diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/array/AbstractOperatorFromSubplanRewrite.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/array/AbstractOperatorFromSubplanRewrite.java
index 530596d..acd557e 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/array/AbstractOperatorFromSubplanRewrite.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/array/AbstractOperatorFromSubplanRewrite.java
@@ -307,7 +307,7 @@
                 break;
         }
 
-        return combinedCondition;
+        return combinedCondition.cloneExpression();
     }
 
     private SelectOperator getSelectFromPlan(AggregateOperator subplanRoot) {
diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/array/JoinFromSubplanRewrite.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/array/JoinFromSubplanRewrite.java
index f4fa0fc..7f003a5 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/array/JoinFromSubplanRewrite.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/array/JoinFromSubplanRewrite.java
@@ -255,9 +255,9 @@
             LogicalVariable newVar = context.newVar();
             VariableReferenceExpression newVarRef = new VariableReferenceExpression(newVar);
             newVarRef.setSourceLocation(joinOp.getSourceLocation());
-            AssignOperator newAssign =
-                    new AssignOperator(newVar, new MutableObject<>(arg.getValue().cloneExpression()));
-            newAssign.setSourceLocation(arg.getValue().getSourceLocation());
+            Mutable<ILogicalExpression> clonedArgRef = new MutableObject<>(arg.getValue().cloneExpression());
+            AssignOperator newAssign = new AssignOperator(newVar, clonedArgRef);
+            newAssign.setSourceLocation(clonedArgRef.getValue().getSourceLocation());
             newAssign.setExecutionMode(joinOp.getExecutionMode());
 
             // Place the new ASSIGN in the appropriate join branch.
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/array-index/atomic-and-array-queries/query8.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/array-index/atomic-and-array-queries/query8.plan
index 4d5a668..3f740b0 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/array-index/atomic-and-array-queries/query8.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/array-index/atomic-and-array-queries/query8.plan
@@ -22,7 +22,7 @@
                             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                               -- PRE_SORTED_DISTINCT_BY  |PARTITIONED|
                                 -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                  -- STABLE_SORT [$$74(ASC), $$75(ASC)]  |PARTITIONED|
+                                  -- STABLE_SORT [$$77(ASC), $$78(ASC)]  |PARTITIONED|
                                     -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                                       -- STREAM_PROJECT  |PARTITIONED|
                                         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
@@ -30,8 +30,9 @@
                                             -- BROADCAST_EXCHANGE  |PARTITIONED|
                                               -- RUNNING_AGGREGATE  |PARTITIONED|
                                                 -- ASSIGN  |PARTITIONED|
-                                                  -- STREAM_PROJECT  |PARTITIONED|
-                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                      -- DATASOURCE_SCAN (TestDataverse.Dataset2)  |PARTITIONED|
-                                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                                  -- ASSIGN  |PARTITIONED|
+                                                    -- STREAM_PROJECT  |PARTITIONED|
+                                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                        -- DATASOURCE_SCAN (TestDataverse.Dataset2)  |PARTITIONED|
+                                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/array-index/atomic-and-array-queries/query9.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/array-index/atomic-and-array-queries/query9.plan
index 5e62aa2..ed318b1 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/array-index/atomic-and-array-queries/query9.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/array-index/atomic-and-array-queries/query9.plan
@@ -31,7 +31,7 @@
                             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                               -- PRE_SORTED_DISTINCT_BY  |PARTITIONED|
                                 -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                  -- STABLE_SORT [$$104(ASC), $$105(ASC)]  |PARTITIONED|
+                                  -- STABLE_SORT [$$108(ASC), $$109(ASC)]  |PARTITIONED|
                                     -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                                       -- STREAM_PROJECT  |PARTITIONED|
                                         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
@@ -39,8 +39,9 @@
                                             -- BROADCAST_EXCHANGE  |PARTITIONED|
                                               -- RUNNING_AGGREGATE  |PARTITIONED|
                                                 -- ASSIGN  |PARTITIONED|
-                                                  -- STREAM_PROJECT  |PARTITIONED|
-                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                      -- DATASOURCE_SCAN (TestDataverse.Dataset2)  |PARTITIONED|
-                                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                                  -- ASSIGN  |PARTITIONED|
+                                                    -- STREAM_PROJECT  |PARTITIONED|
+                                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                        -- DATASOURCE_SCAN (TestDataverse.Dataset2)  |PARTITIONED|
+                                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/array-index/atomic-and-array-queries/query8.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/array-index/atomic-and-array-queries/query8.plan
index 4d5a668..ea7ceef 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/array-index/atomic-and-array-queries/query8.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/array-index/atomic-and-array-queries/query8.plan
@@ -30,8 +30,9 @@
                                             -- BROADCAST_EXCHANGE  |PARTITIONED|
                                               -- RUNNING_AGGREGATE  |PARTITIONED|
                                                 -- ASSIGN  |PARTITIONED|
-                                                  -- STREAM_PROJECT  |PARTITIONED|
-                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                      -- DATASOURCE_SCAN (TestDataverse.Dataset2)  |PARTITIONED|
-                                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                                  -- ASSIGN  |PARTITIONED|
+                                                    -- STREAM_PROJECT  |PARTITIONED|
+                                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                        -- DATASOURCE_SCAN (TestDataverse.Dataset2)  |PARTITIONED|
+                                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/array-index/atomic-and-array-queries/query9.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/array-index/atomic-and-array-queries/query9.plan
index 5e62aa2..b47e122 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/array-index/atomic-and-array-queries/query9.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/array-index/atomic-and-array-queries/query9.plan
@@ -39,8 +39,9 @@
                                             -- BROADCAST_EXCHANGE  |PARTITIONED|
                                               -- RUNNING_AGGREGATE  |PARTITIONED|
                                                 -- ASSIGN  |PARTITIONED|
-                                                  -- STREAM_PROJECT  |PARTITIONED|
-                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                      -- DATASOURCE_SCAN (TestDataverse.Dataset2)  |PARTITIONED|
-                                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                                  -- ASSIGN  |PARTITIONED|
+                                                    -- STREAM_PROJECT  |PARTITIONED|
+                                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                        -- DATASOURCE_SCAN (TestDataverse.Dataset2)  |PARTITIONED|
+                                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|