diff --git a/src/dynamicMesh/clearCodedRedirects.H b/src/dynamicMesh/clearCodedRedirects.H
new file mode 100644
index 0000000..eec857e
--- /dev/null
+++ b/src/dynamicMesh/clearCodedRedirects.H
@@ -0,0 +1,79 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           |
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is a derivative work of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Foam_blastAMR_clearCodedRedirects_H
+#define Foam_blastAMR_clearCodedRedirects_H
+
+#include "fvMesh.H"
+#include "codedFixedValueFvPatchField.H"
+#include "codedMixedFvPatchField.H"
+
+namespace Foam
+{
+
+// Reset cached redirect patch fields on coded BCs (codedFixedValue,
+// codedMixed) after any topology change (refine, unrefine, redistribute).
+//
+// OpenFOAM does not override autoMap/rmap on these BCs to clear the cached
+// redirectPatchFieldPtr_, so it keeps a pointer at the pre-change patch field
+// memory. After autoMap reallocates the parent buffer, the redirect dangles;
+// any user "code" block that writes per-face data buffer-overruns the new
+// patch field, and destruction of the redirect later double-frees / hits an
+// invalid pointer.
+//
+// Workaround: replace each affected patch field with its clone. The
+// codedFixedValueFvPatchField/codedMixedFvPatchField copy constructors
+// initialise redirectPatchFieldPtr_ to null, so the clone has a fresh redirect
+// that is rebuilt lazily on the next updateCoeffs at the correct post-change
+// size.
+template<class GeoField>
+void clearCodedRedirects(fvMesh& mesh)
+{
+    using ValueType = typename GeoField::value_type;
+    using FixedT    = codedFixedValueFvPatchField<ValueType>;
+    using MixedT    = codedMixedFvPatchField<ValueType>;
+
+    HashTable<GeoField*> flds(mesh.template lookupClass<GeoField>());
+    forAllIter(typename HashTable<GeoField*>, flds, iter)
+    {
+        GeoField& fld = *iter();
+        auto& bfld = fld.boundaryFieldRef();
+        forAll(bfld, patchi)
+        {
+            const auto& pf = bfld[patchi];
+            if (isA<FixedT>(pf) || isA<MixedT>(pf))
+            {
+                bfld.set(patchi, pf.clone(fld.internalField()).ptr());
+            }
+        }
+    }
+}
+
+
+// Convenience: clear coded redirects on all common volField types.
+inline void clearCodedRedirectsAllVol(fvMesh& mesh)
+{
+    clearCodedRedirects<volScalarField>(mesh);
+    clearCodedRedirects<volVectorField>(mesh);
+    clearCodedRedirects<volSphericalTensorField>(mesh);
+    clearCodedRedirects<volSymmTensorField>(mesh);
+    clearCodedRedirects<volTensorField>(mesh);
+}
+
+} // End namespace Foam
+
+#endif
diff --git a/src/dynamicMesh/fvMeshBalance/fvMeshBalance.C b/src/dynamicMesh/fvMeshBalance/fvMeshBalance.C
index 3e7ecff..6182621 100644
--- a/src/dynamicMesh/fvMeshBalance/fvMeshBalance.C
+++ b/src/dynamicMesh/fvMeshBalance/fvMeshBalance.C
@@ -33,6 +33,7 @@ License
 #include "preservePatchesConstraint.H"
 #include "preserveBafflesConstraint.H"
 #include "sampledSurfaceWorkaround.H"
+#include "clearCodedRedirects.H"
 #include "dynamicMotionSolverFvMesh.H"
 #include "pointIOField.H"
 
@@ -639,6 +640,10 @@ Foam::fvMeshBalance::distribute()
 
     blastMeshObject::distribute<fvMesh>(mesh_, map());
 
+    // Reset stale codedFixedValue/codedMixed redirects after autoMap.
+    // See clearCodedRedirects.H for rationale.
+    clearCodedRedirectsAllVol(mesh_);
+
     // Expire sampled surfaces in surfaceFieldValue function objects.
     // OpenFOAM's surfaceFieldValue::updateMesh() doesn't properly expire
     // its internal sampledPtr_ cache, leading to stale face indices after
diff --git a/src/dynamicMesh/fvMeshRefiner/fvMeshHexRefiner/fvMeshHexRefiner.C b/src/dynamicMesh/fvMeshRefiner/fvMeshHexRefiner/fvMeshHexRefiner.C
index 9856dfb..b686b7a 100644
--- a/src/dynamicMesh/fvMeshRefiner/fvMeshHexRefiner/fvMeshHexRefiner.C
+++ b/src/dynamicMesh/fvMeshRefiner/fvMeshHexRefiner/fvMeshHexRefiner.C
@@ -30,6 +30,7 @@ License
 
 #include "fvMeshHexRefiner.H"
 #include "addToRunTimeSelectionTable.H"
+#include "clearCodedRedirects.H"
 #include "surfaceInterpolate.H"
 #include "volFields.H"
 #include "polyTopoChange.H"
@@ -229,6 +230,10 @@ Foam::fvMeshHexRefiner::refine
     // would result in double cloud remapping.
     mesh_.updateMesh(map);
 
+    // Reset stale codedFixedValue/codedMixed redirects after autoMap.
+    // See clearCodedRedirects.H for rationale.
+    clearCodedRedirectsAllVol(mesh_);
+
     // Update numbering of protectedCell_
     if (protectedCell_.size())
     {
@@ -322,6 +327,10 @@ Foam::fvMeshHexRefiner::unrefine
     // would result in double cloud remapping.
     mesh_.updateMesh(map);
 
+    // Reset stale codedFixedValue/codedMixed redirects after autoMap.
+    // See clearCodedRedirects.H for rationale.
+    clearCodedRedirectsAllVol(mesh_);
+
     // Update numbering of protectedCell_
     if (protectedCell_.size())
     {
diff --git a/src/dynamicMesh/fvMeshRefiner/fvMeshPolyRefiner/refinement/refinement.C b/src/dynamicMesh/fvMeshRefiner/fvMeshPolyRefiner/refinement/refinement.C
index fb29c56..736fb31 100644
--- a/src/dynamicMesh/fvMeshRefiner/fvMeshPolyRefiner/refinement/refinement.C
+++ b/src/dynamicMesh/fvMeshRefiner/fvMeshPolyRefiner/refinement/refinement.C
@@ -25,6 +25,8 @@ License
 
 #include "refinement.H"
 #include "polyTopoChanger.H"
+#include "clearCodedRedirects.H"
+#include "fvMesh.H"
 #include "polyAddFace.H"
 #include "polyAddPoint.H"
 #include "polyModifyFace.H"
@@ -908,6 +910,11 @@ Foam::autoPtr<Foam::mapPolyMesh> Foam::refinement::refine
     autoPtr<mapPolyMesh> map = meshMod.changeMesh(mesh, false);
     mesh.updateMesh(map());
 
+    if (auto* fvm = dynamic_cast<fvMesh*>(&mesh))
+    {
+        clearCodedRedirectsAllVol(*fvm);
+    }
+
     Info<< "Refined from "
         << returnReduce(map().nOldCells(), sumOp<label>())
         << " to " << mesh_.globalData().nTotalCells() << " cells." << endl;
@@ -926,6 +933,11 @@ bool Foam::refinement::unrefine
     autoPtr<mapPolyMesh> map = meshMod.changeMesh(mesh, false);
     mesh.updateMesh(map());
 
+    if (auto* fvm = dynamic_cast<fvMesh*>(&mesh))
+    {
+        clearCodedRedirectsAllVol(*fvm);
+    }
+
     Info<< "Unrefined from "
         << returnReduce(map().nOldCells(), sumOp<label>())
         << " to " << mesh_.globalData().nTotalCells() << " cells."