IS BROKEN CHANGES ? update attributes by /cart/update.js delete another attributes

I have acode that update cart attributes twice:

  1. Using the HTML “name” definition

  1. Using a JS api request
var request = {
   method: 'POST', headers: headers,
   body: JSON.stringify({ attributes: { 
        'all-in-one': null , 
        'data': null
        } 
   })
};
fetch('/cart/update.js', request).then(function() { location.href = '/cart'; });

The updates are performed on different fields in the attributes
It has worked fine for me so far

Starting today with every update the previous updating is deleted!!!

I would appreciate your help

I found a workaround, I checked and it works fine
Repeated use of “/cart/update.js” service request does not overwrite data
I removed the “name” HTML definition and added handling the update of the value by JS code

How? Do you have an example?