Does not update `false` values

Hi!

We have noticed some strange behavior with Redis Object Cache. If the cache is enabled we can not update checkboxes to a false state in our wp_options database table. You can run into the issue with the following example:

add_action('customize_register', function ($wp_customize) {
    add_option('testc_checkbox_setting_id', true);
    $wp_customize->add_setting('testc_checkbox_setting_id', [
        'type' => 'option',
        'sanitize_callback' => function ($checked) {
            return isset($checked) && true == $checked ? true : false;
        }
    ]);

    $wp_customize->add_control('testc_checkbox_setting_id', [
        'type' => 'checkbox',
        'section' => 'static_front_page',
        'label' => __('Custom Checkbox'),
        'description' => __('This is a custom checkbox input.'),
        'settings' => 'testc_checkbox_setting_id'
    ]);
});

This code simply registers a new checkbox in Design > Customizer > Homepage Settings > “CUSTOM CHECKBOX”. If you try now to deactivate the checkbox (state: not checked), the value never gets updated in the database.

If we deactivate the Redis object cache, all is working fine.

Status: Connected
Client: PhpRedis (v5.2.2)
Drop-in: Valid
Disabled: No
Filesystem: Working
Ping: 1
Errors: []
PhpRedis: 5.2.2
Predis: Not loaded
Credis: Not loaded
PHP Version: 7.4.6
Plugin Version: 2.0.8
Redis Version: 6.0.3
Multisite: No
Global Prefix: "wp_"
Blog Prefix: "wp_"
WP_REDIS_HOST: "redis"
WP_REDIS_MAXTTL: "14400"
WP_REDIS_PREFIX: "wp.io_obj:"
WP_CACHE_KEY_SALT: "wp.io_obj:"
Global Groups: [
    "blog-details",
    "blog-id-cache",
    "blog-lookup",
    "global-posts",
    "networks",
    "rss",
    "sites",
    "site-details",
    "site-lookup",
    "site-options",
    "site-transient",
    "users",
    "useremail",
    "userlogins",
    "usermeta",
    "user_meta",
    "userslugs",
    "blog_meta"
]
Ignored Groups: [
    "counts",
    "plugins",
    "themes",
    "mailster",
    "WPML_ST_Package_Factory"
]
Unflushable Groups: []
Drop-ins: [
    "maintenance.php v by ",
    "Redis Object Cache Drop-In v2.0.8 by Till Krüss"
]

Regards,
Matthew 🙂