ok, I’ve got temporary solution.
Line 1481: yous should have (inside function groups_create_group() / case 2:)
do_action( ‘groups_create_group_step2_save’ );
I’ve added this line:
So it works, but i had to modify this file which I am not happy with. I guess there is another way of doing this properly. If anyone will find better solution, could you please let me know too?