og_field_widget_form: Warning array_diff, line 77 of og.field.inc

Now getting the following warning with the git dev build from 2013-08-23, with registration form on an existing site as well as on a new fresh install:

Warning: array_diff() [function.array-diff]: Argument #2 is not an array in og_field_widget_form() (line 77 of /var/xxxxxx/html/profiles/openatrium/modules/contrib/og/includes/og.field.inc).

Noticed that a patch has been applied to the og_field_widget_form:
og-field-user-membership-2060655-1.patch

to the function og_field_widget_form(&$form, &$form_state, $field, $instance, $langcode.

Any help would be appreciated to get rid of this warning.

edit: Just noticed that the error has already been reported under 2073229