diff --git a/src/V3UndrivenCapture.cpp b/src/V3UndrivenCapture.cpp
index ec6e23846..cd6d84c76 100644
--- a/src/V3UndrivenCapture.cpp
+++ b/src/V3UndrivenCapture.cpp
@@ -101,10 +101,10 @@ void V3UndrivenCapture::sortUniqueVars(std::vector<AstVar*>& vec) {
     vec.erase(std::unique(vec.begin(), vec.end()), vec.end());
 }
 
-void V3UndrivenCapture::sortUniqueFTasks(std::vector<const AstNodeFTask*>& vec) {
-    std::sort(vec.begin(), vec.end());
-    vec.erase(std::unique(vec.begin(), vec.end()), vec.end());
-}
+//void V3UndrivenCapture::sortUniqueFTasks(std::vector<const AstNodeFTask*>& vec) {
+//    std::sort(vec.begin(), vec.end());
+//    vec.erase(std::unique(vec.begin(), vec.end()), vec.end());
+//}
 
 V3UndrivenCapture::V3UndrivenCapture(AstNetlist* netlistp) {
     gather(netlistp);
@@ -112,7 +112,7 @@ V3UndrivenCapture::V3UndrivenCapture(AstNetlist* netlistp) {
     // Normalize direct lists
     for (auto& kv : m_info) {
         sortUniqueVars(kv.second.directWrites);
-        sortUniqueFTasks(kv.second.callees);
+        //sortUniqueFTasks(kv.second.callees);
     }
 
     // Compute summaries for all tasks
@@ -194,8 +194,13 @@ void V3UndrivenCapture::noteDirectWrite(const AstNodeFTask* taskp, AstVar* varp)
 }
 
 void V3UndrivenCapture::noteCallEdge(const AstNodeFTask* callerp, const AstNodeFTask* calleep) {
-    m_info[callerp].callees.push_back(calleep);
-    (void)m_info[calleep];  // ensure callee entry exists
+    //m_info[callerp].callees.push_back(calleep);
+    //(void)m_info[calleep];  // ensure callee entry exists
+    FTaskInfo& callerInfo = m_info[callerp];
+    if (callerInfo.calleesSet.insert(calleep).second) {
+        callerInfo.callees.push_back(calleep);
+    }
+    (void)m_info[calleep];
 }
 
 void V3UndrivenCapture::debugDumpTask(const AstNodeFTask* taskp, int level) const {
diff --git a/src/V3UndrivenCapture.h b/src/V3UndrivenCapture.h
index 3e0646c6b..d16e9e072 100644
--- a/src/V3UndrivenCapture.h
+++ b/src/V3UndrivenCapture.h
@@ -55,6 +55,9 @@ public:
         std::vector<AstVar*> writeSummary;
         // State for writeSummary computation.
         State state = State::UNVISITED;
+        // This is used to test whether weve already recorded a callee.  Used to 'filter' on insert
+        // versus sorting at the end.
+        std::unordered_set<const AstNodeFTask*> calleesSet;
     };
 
     // Enable writeSummary computation.  If disabled, then the existing V3Undriven behaviour is
@@ -74,7 +77,7 @@ private:
     static void sortUniqueVars(std::vector<AstVar*>& vec);
     // Sort and remove duplicates from a vector of callees.  The visitor can record the same callee
     // multiple times (multiple call sites, branches, etc).
-    static void sortUniqueFTasks(std::vector<const AstNodeFTask*>& vec);
+    //static void sortUniqueFTasks(std::vector<const AstNodeFTask*>& vec);
 
     // Collect direct writes and call edges for all tasks/functions.  Run one time when
     // UndrivenCapture is created.  This runs the visitor over the tree.