Buildmode not switched

Context debug shows that context is active, but no buildmode is switched. Switching buildmode with "ND switch build modes" module works fine.

Context 3.0
DS 1.4
ND 2.4
ND Contrib 2.4

Here's my context:

$context = new stdClass;
$context->disabled = FALSE; /* Edit this to true to make a default context disabled initially */
$context->api_version = 3;
$context->name = 'test';
$context->description = '';
$context->tag = '';
$context->conditions = array(
  'node' => array(
    'values' => array(
      'page' => 'page',
    ),
    'options' => array(
      'node_form' => '0',
    ),
  ),
);
$context->reactions = array(
  'debug' => array(
    'debug' => 1,
  ),
  'nd_context_bm' => 'radio',
);
$context->condition_mode = 1;