Lazy builder attached

Edit : Have prefix and suffix in the build render array generate an error too.

The actual render array adding the lazy builder might help here. Impossible to see what the issue is with the current code examples.

I need to precise that I have no problem with my others Lazy Builder.

public static function trustedCallbacks() {
    return ['LoadData'];
  }

public function LoadData($var) {
    $data = $this->dataTakeTime();
    $my_js_var = $data['specific_data'];
    $build = ['#theme' => 'custom_template', '#data' => $data];
    $build['#attached']['library'][] = 'my_module/my_library';
    $build['#attached']['drupalSettings']['myJsVar'] = $my_js_var;
    return $build;
  }

//Partie DVF
  $variables['dvf'] = [
    '#create_placeholder' => TRUE,
    '#lazy_builder' => [
      Dvf::class.':LoadData',
      [$points[0]['lat'], $points[0]['lon']],
    ],
  ];