diff --git a/gtsam/inference/JunctionTree-inst.h b/gtsam/inference/JunctionTree-inst.h
index 99e11084a..b3ec1fc98 100644
--- a/gtsam/inference/JunctionTree-inst.h
+++ b/gtsam/inference/JunctionTree-inst.h
@@ -208,7 +208,7 @@ namespace gtsam {
         // putting orphan subtrees in the index - they'll already be in the index of the ISAM2
         // object they're added to.
         BOOST_FOREACH(const Key& j, myData.bayesTreeNode->conditional()->frontals())
-          nodesIndex.insert(std::make_pair(j, myData.bayesTreeNode)).second;
+          nodesIndex.insert(std::make_pair(j, myData.bayesTreeNode));
 
         // Store remaining factor in parent's gathered factors
         if(!eliminationResult.second->empty())