diff --git a/installer/templates/phx_web/components/core_components.ex b/installer/templates/phx_web/components/core_components.ex
index 85586fecaf..6f7d48c674 100644
--- a/installer/templates/phx_web/components/core_components.ex
+++ b/installer/templates/phx_web/components/core_components.ex
@@ -97,7 +97,7 @@ defmodule <%= @web_namespace %>.CoreComponents do
       <.flash kind={:info} flash={@flash} />
       <.flash kind={:info} phx-mounted={show("#flash")}>Welcome Back!</.flash>
   """
-  attr :id, :string, default: nil, doc: "the optional id of flash container"
+  attr :id, :string, doc: "the optional id of flash container"
   attr :flash, :map, default: %{}, doc: "the map of flash messages to display"
   attr :title, :string, default: nil
   attr :kind, :atom, values: [:info, :error], doc: "used for styling and flash lookup"
diff --git a/priv/templates/phx.gen.live/core_components.ex b/priv/templates/phx.gen.live/core_components.ex
index 85586fecaf..6f7d48c674 100644
--- a/priv/templates/phx.gen.live/core_components.ex
+++ b/priv/templates/phx.gen.live/core_components.ex
@@ -97,7 +97,7 @@ defmodule <%= @web_namespace %>.CoreComponents do
       <.flash kind={:info} flash={@flash} />
       <.flash kind={:info} phx-mounted={show("#flash")}>Welcome Back!</.flash>
   """
-  attr :id, :string, default: nil, doc: "the optional id of flash container"
+  attr :id, :string, doc: "the optional id of flash container"
   attr :flash, :map, default: %{}, doc: "the map of flash messages to display"
   attr :title, :string, default: nil
   attr :kind, :atom, values: [:info, :error], doc: "used for styling and flash lookup"