diff a/src/hotspot/cpu/zero/zeroInterpreter_zero.cpp b/src/hotspot/cpu/zero/zeroInterpreter_zero.cpp
--- a/src/hotspot/cpu/zero/zeroInterpreter_zero.cpp
+++ b/src/hotspot/cpu/zero/zeroInterpreter_zero.cpp
@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2003, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2026, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2007, 2008, 2009, 2010, 2011 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
@@ -580,10 +580,16 @@
   ResolvedFieldEntry* entry = cache->resolved_field_entry_at(index);
   if (!entry->is_resolved(Bytecodes::_getfield)) {
     return normal_entry(method, 0, THREAD);
   }
 
+  // Flattened entries require handling beyond a direct field load.
+  // Bail to slow path.
+  if (entry->is_flat()) {
+    return normal_entry(method, 0, THREAD);
+  }
+
   ZeroStack* stack = thread->zero_stack();
   intptr_t* topOfStack = stack->sp();
 
   // Load the object pointer and drop into the slow path
   // if we have a NullPointerException
@@ -671,10 +677,16 @@
   ResolvedFieldEntry* entry = cache->resolved_field_entry_at(index);
   if (!entry->is_resolved(Bytecodes::_putfield)) {
     return normal_entry(method, 0, THREAD);
   }
 
+  // Flattened entries require handling beyond a direct field store.
+  // Bail to slow path.
+  if (entry->is_flat()) {
+    return normal_entry(method, 0, THREAD);
+  }
+
   ZeroStack* stack = thread->zero_stack();
   intptr_t* topOfStack = stack->sp();
 
   // Figure out where the receiver is. If there is a long/double
   // operand on stack top, then receiver is two slots down.