When recreating a feature after unselecting an incorrectly autodetected dependency I got the following error.

Notice: Undefined index: values in features_plumber_ui_export_build_form_populate() (line 105 of /var/www/html/uc/sites/all/modules/features_plumber/features_plumber_ui/features_plumber_ui.module).

But it did appear to work correctly. Running the latest releases of features, features_tools, etc.