Bad state: Future already completed

[PawlikMichal25]

I've been getting quite a lot of Bad state: Future already completed errors.

They are thrown in /opt/hostedtoolcache/flutter/3.16.9-stable/x64/.pub-cache/hosted/pub.dev/web_socket_channel-2.4.0/lib/html.dart in HtmlWebSocketChannel.<anonymous function> at line 103:7 which seems to point to _readyCompleter.completeError(error); in

    innerWebSocket.onError.first.then((_) {
      final error = WebSocketChannelException('WebSocket connection failed.');
      _readyCompleter.completeError(error);
      _controller.local.sink.addError(error);
      _controller.local.sink.close();
    });

unfortunately I don't have repro steps.
Do you have any advice what's wrong?