diff --git a/src/ast/UserDefinedAggregator.cpp b/src/ast/UserDefinedAggregator.cpp
index ba44e0f7a86..d924a47bbca 100644
--- a/src/ast/UserDefinedAggregator.cpp
+++ b/src/ast/UserDefinedAggregator.cpp
@@ -34,10 +34,9 @@ Node::NodeVec UserDefinedAggregator::getChildren() const {
 }
 
 void UserDefinedAggregator::print(std::ostream& os) const {
-    os << "@" << name;
-    os << " init: " << *initValue;
+    os << "@@" << name << " " << *initValue;
     if (targetExpression) {
-        os << " " << *targetExpression;
+        os << ", " << *targetExpression;
     }
     os << " : { " << join(body) << " }";
 }
diff --git a/src/ram/Aggregate.h b/src/ram/Aggregate.h
index 5c967277348..d59145d26e9 100644
--- a/src/ram/Aggregate.h
+++ b/src/ram/Aggregate.h
@@ -63,6 +63,7 @@ class Aggregate : public RelationOperation, public AbstractAggregate {
         RelationOperation::apply(map);
         condition = map(std::move(condition));
         expression = map(std::move(expression));
+        function->apply(map);
     }
 
     static bool classof(const Node* n) {
diff --git a/src/ram/Aggregator.h b/src/ram/Aggregator.h
index 89608c2fb1f..7514a4a7e08 100644
--- a/src/ram/Aggregator.h
+++ b/src/ram/Aggregator.h
@@ -45,6 +45,8 @@ class Aggregator {
         return {};
     }
 
+    virtual void apply(const NodeMapper&) {}
+
     /**
      * @brief Create a cloning (i.e. deep copy) of this node
      */
diff --git a/src/ram/IndexAggregate.h b/src/ram/IndexAggregate.h
index b9fb90049cf..3b7d6c80a42 100644
--- a/src/ram/IndexAggregate.h
+++ b/src/ram/IndexAggregate.h
@@ -66,6 +66,7 @@ class IndexAggregate : public IndexOperation, public AbstractAggregate {
         IndexOperation::apply(map);
         condition = map(std::move(condition));
         expression = map(std::move(expression));
+        function->apply(map);
     }
 
     static bool classof(const Node* n) {
diff --git a/src/ram/UserDefinedAggregator.h b/src/ram/UserDefinedAggregator.h
index 4c46d873afe..ce83442aeb9 100644
--- a/src/ram/UserDefinedAggregator.h
+++ b/src/ram/UserDefinedAggregator.h
@@ -77,6 +77,10 @@ class UserDefinedAggregator : public Aggregator {
         os << name << " INIT " << *initValue << " ";
     }
 
+    void apply(const NodeMapper& map) override {
+        initValue = map(std::move(initValue));
+    }
+
 protected:
     /** Aggregation function */
     const std::string name;
@@ -92,4 +96,4 @@ class UserDefinedAggregator : public Aggregator {
     /** Stateful */
     const bool stateful;
 };
-}  // namespace souffle::ram
\ No newline at end of file
+}  // namespace souffle::ram