Designing repeat

Hello Dear all!
I am new to this forum and a beginner with ODK. My name is Héritier.
I took an old xls form which I am adapting from a report that I have to conduct in nutrition. I wanted to use the repeat function. But unfortunately in the execution of the application, the smartphone displays an error message as follows: Error evaluating fields '2Z': can't set data value for node that has children!

It would be better if you could attach your XLS file. Before get the solution you could check the documents on repeat:
https://docs.opendatakit.org/form-logic/#repeating-groups-of-questions
http://xlsform.org/en/#repeats

and validate XLSForm here