Steps to reproduce the issue

• I don't know how to reproduce it. I see these messages with n3t debugger plugin activated.
  • Creation of dynamic property Joomla\CMS\Cache\Storage\FileStorage::$_threshold is deprecated. (libraries\src\Cache\CacheStorage.php:108).
  • Creation of dynamic property Joomla\Component\Content\Site\View\Category\HtmlView::$baseurl is deprecated. (libraries\src\MVC\View\HtmlView.php:165)
  • Creation of dynamic property Joomla\CMS\Object\CMSObject::$task (libraries\src\Object\CMSObject.php:186)
  • Creation of dynamic property Joomla\CMS\Object\CMSObject::$parameters.menu (libraries\src\Object\CMSObject.php:186)

While I was able to fix the first ones amateurishly, I have no idea how to do it with the last one (and stopped debugging).