Can using multiple registries in a PHP application lead to confusion or conflicts in managing object instances?

Using multiple registries in a PHP application can lead to confusion and conflicts in managing object instances because different registries may store different instances of the same object or have different states of the same object. To solve this issue, it's recommended to use a single registry or a dependency injection container to manage object instances consistently throughout the application.

class Registry {
    private static $instances = [];

    public static function set($key, $value) {
        self::$instances[$key] = $value;
    }

    public static function get($key) {
        return self::$instances[$key];
    }
}

// Example of using the Registry
Registry::set('db', new Database());
$db = Registry::get('db');