diff --git a/devito/ir/equations/algorithms.py b/devito/ir/equations/algorithms.py
index b3a78c0ebe..8fbc7cca5e 100644
--- a/devito/ir/equations/algorithms.py
+++ b/devito/ir/equations/algorithms.py
@@ -339,3 +339,4 @@ def _(d, mapper, rebuilt, sregistry):
     kwargs['functions'] = functions
 
     mapper[d] = d._rebuild(**kwargs)
+    mapper.update({tkn0: tkn1 for tkn0, tkn1 in zip(d.thickness, tkns, strict=True)})