mix phx.routes shows wrong socket information for (nth) endpoint, n > 1

[ityonemo]

trafficstars

Environment

Erlang/OTP 24 [erts-12.0.2] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit]

Elixir 1.12.0 (compiled with Erlang/OTP 24)

phoenix 1.5.9 (Hex package) (mix)

Steps to reproduce.

mix phx.new yolo
cp lib/yolo_web/endpoint.ex lib/yolo_web/endpoint2.ex
cp lib/yolo_web/router.ex lib/yolo_web/router2.ex

edit modules to be YoloWeb.Endpoint2 and YoloWeb.Router2 edit YoloWeb.Endpoint2 module to have plug YoloWeb.Router2 at the bottom

comment out sockets from YoloWeb.Endpoint2 comment out livedashboard stuff from both routers.

Expected behavior

mix phx.routes YoloWeb.Router2 shows no sockets:

          page_path  GET  /                                      YoloWeb.PageController :index

Actual behavior

mix phx.routes YoloWeb.Router2 shows socket information from YoloWeb.Endpoint:

          page_path  GET  /                                      YoloWeb.PageController :index
          websocket  WS   /live/websocket                        Phoenix.LiveView.Socket
           longpoll  GET  /live/longpoll                         Phoenix.LiveView.Socket
           longpoll  POST  /live/longpoll                         Phoenix.LiveView.Socket
          websocket  WS   /socket/websocket                      YoloWeb.UserSocket

Note

the reverse works, too. Commenting out socket information from YoloWeb.Endpoint and keeping in YoloWeb.Endpoint2 results in no sockets shown on YoloWeb.Endpoint2