gistfile1.txt

add_filter( "propertyhive_arthur_json_properties_due_import", 'property_tags_on_unit', 10, 2 );
function property_tags_on_unit( $properties, $import_id )
{
    foreach ( $properties as $i => $property )
    {
        $tags = isset($property['tags']) && !empty($property['tags']) ? $property['tags'] : array();
        
        if ( !empty($tags) )
        {
            if (
				isset($property['units']) && is_array($property['units']) && !empty($property['units']) 
			)
			{
				foreach ( $property['units'] as $unit_i => $unit )
				{
                    $unit_tags = isset($unit['tags']) && !empty($unit['tags']) ? $unit['tags'] : array();
                    
                    $unit_tags = array_merge($unit_tags, $tags);
                    $unit_tags = array_unique($unit_tags);
                    
                    $properties[$i]['units'][$unit_i]['tags'] = $unit_tags;
                }
            }
        }
    }
    
    return $properties;
}