Removing the full Schema
There have a filter fl_post_grid_disable_schema in BB Post Module. You can easily disable the schema via this simple PHP code.
add_filter( 'fl_post_grid_disable_schema', '__return_true' );
Removing only Author Schema
add_filter( 'fl_schema_meta_author', '__return_null' );
Removing Publisher Schema
add_filter( 'fl_schema_meta_publisher', '__return_null' );
Removing Publish Date Schema
add_filter( 'fl_schema_meta_general', '__return_null' );
Removing Comments Schema
add_filter( 'fl_schema_meta_comments', '__return_null' );
Removing Featured Image Schema
add_filter( 'fl_schema_meta_thumbnail', '__return_null' );
Where Shall I Place The Code?
In the WordPress Dashboard, go to Appearance > Theme Editor and open the functions.php file of your child theme. Then add the following code at the end. Alternatively, you can use code snippets plugin for adding custom code.