Notice: Undefined index: is_hidden when editing answer (ajax)

Hi,
using latest makemeeting module version from git branch 7.x-2.x

Full error message from dblog:
Notice: Undefined index: is_hidden in theme_makemeeting_answers() (line 268 of .../sites/all/modules/makemeeting/makemeeting.theme.inc).

When creating a new answer, is_hidden is correctly set (boolean), but when editing existing answers via the ajax form, is_hidden is missing in $item array.
Not sure why this happens.