BuddyPress.org

Just for reference… This works on a basic installation:

// add order options to members loop
function pp_member_order_options() {
	?>
	<option value="alphabetical-last"><?php _e( 'Alphabetical - Last Name', 'buddypress' ); ?></option>
	<?php
}
add_action( 'bp_members_directory_order_options', 'pp_member_order_options' );

function pp_members_loop_selection( $bp_user_query ) {

	//  if Order By is set to alphabetical-last, sort by last name
	if ( 'alphabetical-last' == $bp_user_query->query_vars['type'] ) {
		$bp_user_query->uid_clauses['orderby'] = "ORDER BY substring_index(u.display_name, ' ', -1)";
	   
		// if they have variable last names like: Jones de Smith
		//$bp_user_query->uid_clauses['orderby'] = "ORDER BY substring_index( substring_index(u.display_name, ' ', 2), ' ', -1 )";
	}

}
add_action ( 'bp_pre_user_query', 'pp_members_loop_selection', 20 );

The bp_pre_user_query hook is very powerful, but if anything else on your site is using it then the results can be confusing.

When you post complaints without any details then you will get no support.
BuddyPress is an open-source product.
You should hire a developer to help you.

I cannot duplicate your issue with a WP theme like 2019.

Here are some basic questions to help you narrow down the issue:

Did BuddyBoss do their tests on your site or theirs ?

Are you trying to delete from the front-end or the back-end?
What kind of group is it – public, private, hidden ?

Which BP template are you using?

Did you check your error logs ?

Have you try deactivating other plugins?

If you can list the steps to create the issue – be specific and include screenshots – you could open a ticket here. Be sure to reference this thread.

could try
https://codex.wordpress.org/Shortcode_API#Output
and
codex.buddypress.org/developer/loops-reference/the-blogs-loop/

Create a ticket here: https://buddypress.trac.wordpress.org/newticket

Find the /buddypress/members/single/profile/change-avatar.php file and place a copy in your child theme’s /buddypress/members/single/profile/ folder and modify that file by removing the parts about gravatar

or this maybe

Loco Translate

I have the same issue. I hope BuddyPress folks are on board for support. nearly two weeks after the above post.

Deactivate Youser for now.
Get a basic BP install working first.

Walk thru the Configure guide and the Admin guide instructions in the codex.

Resave your permalinks after choosing any option other than the default option.

I’m not saying that it will solve all your issues, but it will get you on the right track.

BuddyPress does not include forums.

If you are using bbPress, you should ask on their support forums.

Finding out which words are triggering a filter can be difficult. The people at bbPress should be able to provide specifics re their filter.
If the issue about WP comments rather than forum lists, you could ask on the WP support forums.