Taxonomy selects first value when should show blank

Hello,

I have an issue on my user form. I have a taxonomy field, eg:

        $field= [
                'name' => __( 'Main research area', 'your-text-domain' ),
                'id'   => 'research_area',
                'type' => 'taxonomy_advanced',
                'taxonomy' => ['expertise-area'],  
                'field_type'    => 'select_advanced',
                'multiple'      => true,
                 'ajax' => true,
                 
        ];

And it autoselects the first value.

It is not just this taxonomy, but every taxonomy_advanced which uses select_advanced

I tried adding 'std' = ''; - didn't fix it