Debugging Turbo not Handling Form

Any advice on debugging why Turbo is not handling a particular form?

I am using Turbo Rails and drive mode is working flawlessly for normal navigation, but a particular form that I’m trying to use with stream does not seem to be handled by Turbo. The browser is submitting the form as normal. Form looks like:

<%= turbo_frame_tag "#{dom_id(chat)}_chat_message_form" do %>
  <%= form_with(model:, url: chat_chat_messages_path(format: :turbo_stream)) do |form| %>
    <div class="my-5">
      <%= form.text_area :message, rows: 4, class: "block shadow rounded-md border border-gray-200 outline-none px-3 py-2 mt-2 w-full", autofocus: true, "x-on:keydown.cmd.enter" => "$;" %>

    <div class="grid justify-items-end">
      <%= form.button type: :submit, class: "rounded-lg py-3 px-5 bg-blue-600 text-white inline-block font-medium cursor-pointer" do %>
        <i class="fas fa-paper-plane"></i>
        <span class="pl-2">Send</span>
      <% end %>
  <% end %>
<% end %>

The x-on:keydown.cmd.enter is also not working. Stimulus and Turbo are working elsewhere so I am really stumped by this.

Same issue as here, but I think I narrowed it down to Turbo not preventing default on the form: Turbo Not Accepting Turbo Stream - rubyonrails-talk - Ruby on Rails Discussions

Web inspector is showing some events on the frame (though not specifically on the form–not sure if that matters):

Found the issue! See here: Turbo ignores form ending with action ending in parameter · Issue #1069 · hotwired/turbo · GitHub

Under normal circumstances, format: :turbo_stream shouldn’t be necessary, just chat_chat_messages_path should work. When turbo submits the form, it sets the corresponding header so that the request is recognized as turbo stream by Rails. (See: Turbo Handbook)