1 files changed, 1 insertions, 1 deletions
diff --git a/activesupport/lib/active_support/hash_with_indifferent_access.rb b/activesupport/lib/active_support/hash_with_indifferent_access.rb
index 1468c62151..4f71f13971 100644
--- a/activesupport/lib/active_support/hash_with_indifferent_access.rb
+++ b/activesupport/lib/active_support/hash_with_indifferent_access.rb
@@ -267,7 +267,7 @@ module ActiveSupport
             value.nested_under_indifferent_access
           end
         elsif value.is_a?(Array)
-          unless options[:for] == :assignment
+          if options[:for] != :assignment || value.frozen?
             value = value.dup
           end
           value.map! { |e| convert_value(e, options) }