diff --git a/src/coreclr/jit/compiler.h b/src/coreclr/jit/compiler.h
index c0a60c66ad76bc..07431d8a14e803 100644
--- a/src/coreclr/jit/compiler.h
+++ b/src/coreclr/jit/compiler.h
@@ -2091,6 +2091,9 @@ class FlowGraphNaturalLoop
     // Can be used to store additional annotations for this loop on the side.
     unsigned m_index = 0;
 
+    // True if this loop contains an improper loop header
+    bool m_containsImproperHeader = false;
+
     FlowGraphNaturalLoop(const FlowGraphDfsTree* dfsTree, BasicBlock* head);
 
     unsigned LoopBlockBitVecIndex(BasicBlock* block);
@@ -2179,6 +2182,11 @@ class FlowGraphNaturalLoop
     bool ContainsBlock(BasicBlock* block);
     bool ContainsLoop(FlowGraphNaturalLoop* childLoop);
 
+    bool ContainsImproperHeader() const
+    {
+        return m_containsImproperHeader;
+    }
+
     unsigned NumLoopBlocks();
 
     template<typename TFunc>
diff --git a/src/coreclr/jit/fgprofilesynthesis.cpp b/src/coreclr/jit/fgprofilesynthesis.cpp
index 2de615136cfeb4..0ab8576cb24b86 100644
--- a/src/coreclr/jit/fgprofilesynthesis.cpp
+++ b/src/coreclr/jit/fgprofilesynthesis.cpp
@@ -1193,12 +1193,14 @@ void ProfileSynthesis::GaussSeidelSolver()
             //
             if (block->bbPreds != nullptr)
             {
-                // Leverage Cp for existing loop headers.
+                // Leverage Cp for existing loop headers, provided that
+                // all contained loops are proper.
+                //
                 // This is an optimization to speed convergence.
                 //
                 FlowGraphNaturalLoop* const loop = m_loops->GetLoopByHeader(block);
 
-                if (loop != nullptr)
+                if ((loop != nullptr) && !loop->ContainsImproperHeader())
                 {
                     // Sum all entry edges that aren't EH flow
                     //
diff --git a/src/coreclr/jit/flowgraph.cpp b/src/coreclr/jit/flowgraph.cpp
index 9b9f3a3f951418..e2f450a7cb194d 100644
--- a/src/coreclr/jit/flowgraph.cpp
+++ b/src/coreclr/jit/flowgraph.cpp
@@ -4386,6 +4386,15 @@ FlowGraphNaturalLoops* FlowGraphNaturalLoops::Find(const FlowGraphDfsTree* dfsTr
         if (!FindNaturalLoopBlocks(loop, worklist))
         {
             loops->m_improperLoopHeaders++;
+
+            for (FlowGraphNaturalLoop* const otherLoop : loops->InPostOrder())
+            {
+                if (otherLoop->ContainsBlock(header))
+                {
+                    otherLoop->m_containsImproperHeader = true;
+                }
+            }
+
             continue;
         }