diff --git a/src/mudlib/zmachine/quetzal.py b/src/mudlib/zmachine/quetzal.py
index 927e25e..730eb9d 100644
--- a/src/mudlib/zmachine/quetzal.py
+++ b/src/mudlib/zmachine/quetzal.py
@@ -248,6 +248,12 @@ class QuetzalParser:
                 raise QuetzalStackFrameOverflow
 
         self._zmachine._stackmanager = stackmanager
+        # Update cached references in subsystems that store the stack manager
+        # (they cache the stack at init time and won't see the replacement)
+        if hasattr(self._zmachine, "_cpu"):
+            self._zmachine._cpu._stackmanager = stackmanager
+        if hasattr(self._zmachine, "_opdecoder"):
+            self._zmachine._opdecoder._stack = stackmanager
         log("  Successfully installed all stack frames.")
 
     def _parse_intd(self, data):