SocketIOでページを離れてないのにDisconnectになってしまう

ユーザーがページから離れるとClient disconnectとサーバー(Python)側で出力させたい

ユーザーがアクセスするサイト側でSocket.IOを
サーバー側でPythonのFlask-SocketIOを使用して
ユーザーがページにアクセスするとサーバー(Python)側でConnectと出力し、
ユーザーがページから離れるとClient disconnectとサーバー(Python)側で出力させたい

ですが、タイトルの通り、ユーザーがページを離れていないにも関わらずサーバー側でClient disconnectとなってしまいます。
(connectは正常な動作をします。)

該当のソースコード

Python
1from flask_socketio import SocketIO, emit, join_room, leave_room, \
2    close_room, rooms, disconnect 
3
4@socketio.event
5def my_event(message):
6    session['receive_count'] = session.get('receive_count', 0) + 1
7    emit('my_response',
8         {'data': message['data'], 'count': session['receive_count']})
9
10
11@socketio.event
12def my_broadcast_event(message):
13    session['receive_count'] = session.get('receive_count', 0) + 1
14    emit('my_response',
15         {'data': message['data'], 'count': session['receive_count']},
16         broadcast=True)
17
18@socketio.event
19def join(message):
20    join_room(message['room'])
21    session['receive_count'] = session.get('receive_count', 0) + 1
22    emit('my_response',
23         {'data': 'In rooms: ' + ', '.join(rooms()),
24          'count': session['receive_count']})
25
26
27@socketio.event
28def leave(message):
29    leave_room(message['room'])
30    session['receive_count'] = session.get('receive_count', 0) + 1
31    emit('my_response',
32         {'data': 'In rooms: ' + ', '.join(rooms()),
33          'count': session['receive_count']})
34
35
36@socketio.on('close_room')
37def on_close_room(message):
38    session['receive_count'] = session.get('receive_count', 0) + 1
39    emit('my_response', {'data': 'Room ' + message['room'] + ' is closing.',
40                         'count': session['receive_count']},
41         to=message['room'])
42    close_room(message['room'])
43
44
45@socketio.event
46def my_room_event(message):
47    session['receive_count'] = session.get('receive_count', 0) + 1
48    emit('my_response',
49         {'data': message['data'], 'count': session['receive_count']},
50         to=message['room'])
51
52
53@socketio.event
54def disconnect_request():
55    @copy_current_request_context
56    def can_disconnect():
57        disconnect()
58
59    session['receive_count'] = session.get('receive_count', 0) + 1
60    emit('my_response',
61         {'data': 'Disconnected!', 'count': session['receive_count']},
62         callback=can_disconnect)
63
64
65@socketio.event
66def my_ping():
67    emit('my_pong')
68
69
70@socketio.event
71def connect():
72    global thread
73    with thread_lock:
74        if thread is None:
75            thread = socketio.start_background_task(background_thread)
76    emit('my_response', {'data': 'Connected', 'count': 0})
77
78
79@socketio.on('connect')
80def before_request():
81    print("connected")
82
83try:
84    @socketio.on('disconnect')
85    def test_disconnect():
86        ip_list.clear()
87        print('Client disconnected')
88except socket.error.BrokenPipeError as e:
89    pass

HTML
1<!DOCTYPE html>
2<html lang="en">
3<head>
4    <meta charset="UTF-8">
5    <meta name="viewport" content="width=device-width">
6    <title>Test Server</title>
7    <link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.3.1/css/bootstrap.min.css" rel="stylesheet">
8    <link href="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.css" rel="stylesheet">
9</head>
10<body>
11
12<div id="log"></div>
13
14</body>

JavaScript
1<!--suppress JSUnresolvedLibraryURL -->
2<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.0/jquery.min.js"></script>
3<!--suppress JSUnresolvedLibraryURL -->
4<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.3.1/js/bootstrap.min.js"></script>
5<!--suppress JSUnresolvedLibraryURL -->
6<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.js"></script>
7 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js" integrity="伏せます" crossorigin="anonymous"></script>
8    <script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/3.0.4/socket.io.js" integrity="伏せます" crossorigin="anonymous"></script>
9
10
11$(document).ready(function(){
12            var socket = io();
13            socket.on('connect', function(event) {
14                socket.emit('my_event', {data: 'I\'m connected!'});
15            });
16            socket.on('disconnect',function(event){
17                socket.emit('my_disconnect', {data: 'I\'m disconnected!'});
18           });
19            socket.on('my_response', function(msg, cb) {
20                $('#log').append('<br>' + $('<div/>').text('Received #' + msg.count + ': ' + msg.data).html());
21                if (cb)
22                    cb();
23            });
24            var ping_pong_times = [];
25            var start_time;
26            window.setInterval(function() {
27                start_time = (new Date).getTime();
28                socket.emit('my_ping');
29            }, 1000);
30            socket.on('my_pong', function() {
31                var latency = (new Date).getTime() - start_time;
32                ping_pong_times.push(latency);
33                ping_pong_times = ping_pong_times.slice(-30); // keep last 30 samples
34                var sum = 0;
35                for (var i = 0; i < ping_pong_times.length; i++)
36                   sum += ping_pong_times[i];
37               $('#ping-pong').text(Math.round(10 * sum / ping_pong_times.length) / 10);
38           });
39
40            $('form#emit').submit(function(event) {
41                socket.emit('my_event', {data: $('#emit_data').val()});
42                return false;
43            });
44            $('form#broadcast').submit(function(event) {
45                socket.emit('my_broadcast_event', {data: $('#broadcast_data').val()});
46                return false;
47            });
48            $('form#join').submit(function(event) {
49                socket.emit('join', {room: $('#join_room').val()});
50                return false;
51            });
52            $('form#leave').submit(function(event) {
53                socket.emit('leave', {room: $('#leave_room').val()});
54                return false;
55            });
56            $('form#send_room').submit(function(event) {
57                socket.emit('my_room_event', {room: $('#room_name').val(), data: $('#room_data').val()});
58                return false;
59            });
60            $('form#close').submit(function(event) {
61                socket.emit('close_room', {room: $('#close_room').val()});
62                return false;
63            });
64            
65            $('form#disconnect').submit(function(event) {
66                socket.emit('disconnect_request');
67                return false;
68            });
69
70     }