Edit records via the API

Hello Kobo team:

I am trying to edit submissions via the Kobo API following this instructions:
KoboToolbox Form Building API

This works fine when I update grouped fields, but it gives the following error when trying to update repeating groups:

“Server Error (500)”

I really need to know how to update a repeating group to complete some data.

Thanks in advance.

@adrianguzman, FYI: