Steps Reproduce:
1. Installed the module using Composer with the command: composer require 'drupal/paragraph_group:^2.0'.
2: After enabling this module it throws some warnings, the warnings mentioned below.
Warning: foreach() argument must be of type array|object, null given in Drupal\paragraph_group\Form\ParagroupConfigForm->getSectionDetailsOpen() (line 56 of modules\contrib\paragraph_group\src\Form\ParagroupConfigForm.php).
Warning: foreach() argument must be of type array|object, null given in Drupal\paragraph_group\Form\ParagroupConfigForm->getSectionDetailsOpen() (line 56 of modules\contrib\paragraph_group\src\Form\ParagroupConfigForm.php).
Warning: Undefined array key "node.article.title" in Drupal\paragraph_group\Paragroup\ParagroupFieldGroupManager::getType() (line 247 of modules\contrib\paragraph_group\src\Paragroup\ParagroupFieldGroupManager.php).
Warning: Undefined array key "node.event_page.title" in Drupal\paragraph_group\Paragroup\ParagroupFieldGroupManager::getType() (line 247 of modules\contrib\paragraph_group\src\Paragroup\ParagroupFieldGroupManager.php).
Warning: foreach() argument must be of type array|object, null given in Drupal\paragraph_group\Form\ParagroupConfigForm->getSectionDetailsOpen() (line 56 of modules\contrib\paragraph_group\src\Form\ParagroupConfigForm.php).
Warning: foreach() argument must be of type array|object, null given in Drupal\paragraph_group\Form\ParagroupConfigForm->getSectionDetailsOpen() (line 56 of modules\contrib\paragraph_group\src\Form\ParagroupConfigForm.php).
Warning: foreach() argument must be of type array|object, null given in Drupal\Core\Render\Element\Tableselect::valueCallback() (line 94 of core\lib\Drupal\Core\Render\Element\Tableselect.php).
Warning: foreach() argument must be of type array|object, null given in Drupal\Core\Render\Element\Tableselect::valueCallback() (line 94 of core\lib\Drupal\Core\Render\Element\Tableselect.php).
Warning: foreach() argument must be of type array|object, null given in Drupal\Core\Render\Element\Tableselect::valueCallback() (line 94 of core\lib\Drupal\Core\Render\Element\Tableselect.php).
Warning: foreach() argument must be of type array|object, null given in Drupal\Core\Render\Element\Tableselect::valueCallback() (line 94 of core\lib\Drupal\Core\Render\Element\Tableselect.php).
I've attached an image illustrating my actions—installing the module and searching within the extended panel.