Compatibility with UI patterns 2

we found the solution.

one needs to implement

function ui_patterns_ds_preprocess_ds_entity_view(&$variables) {
   if (isset($variables['content']) && isset($variables['content']['#entity']) && isset($variables['content']['#source_contexts'])
      && is_array($variables['content']['#source_contexts']) && !isset($variables['content']['#source_contexts']["entity"])) {
    $variables['content']['#source_contexts']["entity"] = \Drupal\Core\Plugin\Context\EntityContext::fromEntity($variables['content']['#entity']);
  }
}