ksort() expects parameter 1 to be array, null given in drupal_group_js()

After enabling the module, I get:
Warning: ksort() expects parameter 1 to be array, null given in drupal_group_js() (line 4584 of
/srv/bindings/a0fb8f07137d44b7beed52dbc39a0213/code/includes/common.inc).

I'm using D7.41 with Commerce Kickstart 7.x-2.32