Bug fix on custom dynamic web form odoo15

We have a customer that have some dynamics web forms in v11 and we need fix some bugs to work in v15, the forms are questionnaires builded dynamically based in one2many field questions records, the webform questionnaire has 3 dynamic structures:
section
question
response

The module is already migrated to v15 but we have a bug that is not showing properly the questionnaires in the web frontend