Hi Tosin,
the code is working perfectly from me. I tried the following code(create a copy of Subscriber role and named volunteer)
You ca see the role in Dashboard->Members-> 2nd column of the list

/**
 * Change user role on first login
 */
function buddydev_change_user_role_on_first_login( $user_login, $user ) {

	if ( ! function_exists( 'buddypress' ) || user_can( $user->ID, 'manage_options' ) ) {
		return;
	}

	// check for user's last activity.
	$last_activity = bp_get_user_last_activity( $user->ID );

	if ( empty( $last_activity ) ) {
		$role = 'volunteer'; // please change with your desired role.
		$user->set_role( $role );

	}
}

add_action( 'wp_login', 'buddydev_change_user_role_on_first_login', - 1, 2 );

I tried following use case.

1. Registered a user via Dahsboard->User->New and logged, it changed correctly.
2. Registered from front end using Auto Login and Auto Activation plugin, worked.
3. Disabled Auto Activation plugin, registered a new account, activated using the key and logged, it worked too.

For me, all the use cases are working. Please check the plugins or code that you might be using. They can have some effect on it.

Regards
Brajesh

Hi Hugo,
Thank you for posting.

The Facebook Like Activity does not remove any activity type. It simply merges the streams at one place.

I am unable to guess any reason for it.

Also, by status update, you mean you are using some specific plugin for that?

Thank you
Brajesh