Steps to reproduce the issue

install joomla 5.2 beta
install flexicontent component

Expected result

install joomla 5.1 beta
install flexicontent component
all works

Actual result

to install it need to actived compatibility plugin before

Call stack
--
# | Function | Location
1 | () | JROOT\tmp\install_650a9698d4fc7\flexicontent-cck-master\script.php:26
2 | require_once() | JROOT\libraries\src\Installer\InstallerAdapter.php:962
3 | Joomla\CMS\Installer\InstallerAdapter->setupScriptfile() | JROOT\libraries\src\Installer\InstallerAdapter.php:711
4 | Joomla\CMS\Installer\InstallerAdapter->install() | JROOT\libraries\src\Installer\Installer.php:648
5 | Joomla\CMS\Installer\Installer->install() | JROOT\administrator\components\com_installer\src\Model\InstallModel.php:209
6 | Joomla\Component\Installer\Administrator\Model\InstallModel->install() | JROOT\administrator\components\com_installer\src\Controller\InstallController.php:52
7 | Joomla\Component\Installer\Administrator\Controller\InstallController->install() | JROOT\libraries\src\MVC\Controller\BaseController.php:730
8 | Joomla\CMS\MVC\Controller\BaseController->execute() | JROOT\libraries\src\Dispatcher\ComponentDispatcher.php:143
9 | Joomla\CMS\Dispatcher\ComponentDispatcher->dispatch() | JROOT\libraries\src\Component\ComponentHelper.php:361
10 | Joomla\CMS\Component\ComponentHelper::renderComponent() | JROOT\libraries\src\Application\AdministratorApplication.php:150
11 | Joomla\CMS\Application\AdministratorApplication->dispatch() | JROOT\libraries\src\Application\AdministratorApplication.php:195
12 | Joomla\CMS\Application\AdministratorApplication->doExecute() | JROOT\libraries\src\Application\CMSApplication.php:306
13 | Joomla\CMS\Application\CMSApplication->execute() | JROOT\administrator\includes\app.php:58
14 | require_once() | JROOT\administrator\index.php:32

RuntimeException:
Failed to start the session because headers have already been sent by "C:\wamp64\www\j5\libraries\vendor\joomla\application\src\AbstractWebApplication.php" at line 405.

  at C:\wamp64\www\j5\libraries\vendor\joomla\session\src\Storage\NativeStorage.php:454
  at Joomla\Session\Storage\NativeStorage->start()
     (C:\wamp64\www\j5\libraries\src\Session\Storage\JoomlaStorage.php:313)
  at Joomla\CMS\Session\Storage\JoomlaStorage->start()
     (C:\wamp64\www\j5\libraries\vendor\joomla\session\src\Session.php:396)
  at Joomla\Session\Session->start()
     (C:\wamp64\www\j5\libraries\vendor\joomla\session\src\Session.php:327)
  at Joomla\Session\Session->has('user')
     (C:\wamp64\www\j5\libraries\src\Session\Session.php:194)
  at Joomla\CMS\Session\Session->get('user')
     (C:\wamp64\www\j5\libraries\src\Factory.php:372)
  at Joomla\CMS\Factory::getUser()
     (C:\wamp64\www\j5\libraries\src\Session\Session.php:101)
  at Joomla\CMS\Session\Session::getFormToken()
     (C:\wamp64\www\j5\plugins\system\debug\src\Extension\Debug.php:336)
  at Joomla\Plugin\System\Debug\Extension\Debug->onAfterRespond(object(AfterRespondEvent))
     (C:\wamp64\www\j5\libraries\vendor\joomla\event\src\Dispatcher.php:454)
  at Joomla\Event\Dispatcher->dispatch('onAfterRespond', object(AfterRespondEvent))
     (C:\wamp64\www\j5\libraries\vendor\joomla\application\src\AbstractApplication.php:99)
  at Joomla\Application\AbstractApplication->dispatchEvent('onAfterRespond', object(AfterRespondEvent))
     (C:\wamp64\www\j5\libraries\src\Application\CMSApplication.php:351)
  at Joomla\CMS\Application\CMSApplication->execute()
     (C:\wamp64\www\j5\administrator\includes\app.php:58)
  at require_once('C:\\wamp64\\www\\j5\\administrator\\includes\\app.php')
     (C:\wamp64\www\j5\administrator\index.php:32)