Hi Ada,
when you copied the code from the referenced post, you might have used the following code from step 5.

function bcg_custom_forms_args( $args ) {
	
	$args['tax'] = array();
	
	$cusom_fields = isset( $args['custom_fields'] ) ? $args['custom_fields']: array() ;
	
	$group = groups_get_current_group();
	
	if( empty( $group ) || empty( $group->id ) ) {
		return $args;
	}
	
	$cats = bcg_get_categories( $group->id );
	//if there is no category set
	if( empty( $cats ) ) {
		//create if not exists
		$cats = bcg_custom_create_group_category( $group );
	}
	
	if ( empty( $cats ) ) {
		return $args;
	}
	
	$cusom_fields['_bcg_selected_category'] = array(
		'type'		=> 'hidden',
		'default'	=> $cats[0],
		'label'		=> ''	
	);
	
	$args['custom_fields'] = $cusom_fields;
	$args['post_status'] = 'publish';
	
	return $args;
}
add_filter( 'bcg_form_args', 'bcg_custom_forms_args' );

Please change that to this

function bcg_custom_forms_args( $args ) {

	$tax = $args['tax'];

	unset( $tax['category'] );//we don't need a box for category
	$args['tax'] = $tax;
	$cusom_fields = isset( $args['custom_fields'] ) ? $args['custom_fields']: array() ;

	$group = groups_get_current_group();

	if( empty( $group ) || empty( $group->id ) ) {
		return $args;
	}

	$cats = bcg_get_categories( $group->id );
	//if there is no category set
	if( empty( $cats ) ) {
		//create if not exists
		$cats = bcg_custom_create_group_category( $group );
	}

	if ( empty( $cats ) ) {
		return $args;
	}

	$cusom_fields['_bcg_selected_category'] = array(
		'type'		=> 'hidden',
		'default'	=> $cats[0],
		'label'		=> ''
	);

	$args['custom_fields'] = $cusom_fields;
	$args['post_status'] = 'publish';

	return $args;
}
add_filter( 'bcg_form_args', 'bcg_custom_forms_args' );

We were removing all the taxonomies causing the issue. Updating that section should make it work. Please give it a try. Another small modification may be required if it does not work for you. Please do let me know how it goes with you.

Hi Leo,
Please upgrade to 1.1.3 and It will work.
Hope that helps.

Thank you
Brajesh

Hi Leo,
Thank you for reporting the issue. I am looking at it. will have a solution soon.

Thank you
Brajesh

Thank you for confirming. Please delete it from the admin and download a fresh copy to install/update. to avoid it in future, if you want, you may install BuddyDev dashboard plugin.

Please do check and let me know after the update.

Thank you
Brajesh