I don't have a lot of context, sorry (I'm not the Limesurvey user which encounters that bug).

Page is /admin/questions/sa/answeroptions/surveyid/657833/gid/57/qid/847

AJAX request is /admin/labels/ajaxSets and its POST data is :

array (
'laname' => 'frequence2',
'lid' => '0',
'code' => array (
0 => 'A1',
1 => 'A2',
2 => 'A3',
3 => 'A4',
),
'answers' => array (
'fr' => array (
0 => 'Pas du tout',
1 => 'Occasionnellement',
2 => 'Au moins une fois par semaine',
3 => 'Tous les jours',
),
),
);