Warning: Illegal string offset ‘gpage_id’

(Log in WP_DEBUG mode)
When I enter on group page/Manage/Extras, its apear these mesege :

Warning: Illegal string offset 'display_page' in C:\xampp\htdocs\PRUEBA_1\wp-content\plugins\buddypress-groups-extras\core\loader.php on line 456
Warning: Illegal string offset 'display_gpages' in C:\xampp\htdocs\PRUEBA_1\wp-content\plugins\buddypress-groups-extras\core\loader.php on line 459
Warning: Illegal string offset 'display_page_layout' in C:\xampp\htdocs\PRUEBA_1\wp-content\plugins\buddypress-groups-extras\core\loader.php on line 462

Then when i add a new page on “Extras” its apear these message on the top of the screem:

Warning: Illegal string offset 'gpage_id' in C:\xampp\htdocs\PRUEBA_1\wp-content\plugins\buddypress-groups-extras\core\loader.php on line 1079
Warning: Illegal string offset 'gpage_id' in C:\xampp\htdocs\PRUEBA_1\wp-content\plugins\buddypress-groups-extras\core\loader.php on line 1092
Warning: Illegal string offset 'display_page_layout' in C:\xampp\htdocs\PRUEBA_1\wp-content\plugins\buddypress-groups-extras\core\loader.php on line 80

WordPress 5.5.1
BuddyPress 6.3.0
BuddyPress Groups Extras 3.6.9.1
PHP Version 7.4.8

Can you help me please?
Thanks