My mistake: going up to 5th client doesn't solve the situation with reading whole table data - it did change the structure of the visible information in dev console, but the situation is the same - can't read whole table.
Did some more research, I think now I understand how this works:
1. the mobx library is used in client application to convert form field data structures as observable entities, which registers their state changes
2. in result field values and other config properties are not stored in their original places as it was in 3.36, but mobx is taking care to get/set them on request
3. this technology works instantly if values are simple or a fragment of an object, but if you need to get whole array then it doesn't work so. Here are some discussions regarding it on mobx github site: https://github.com/mobxjs/mobx/issues/1653
4. for such cases there is additional tool in mobx 'https://mobx.js.org/refguide/tojson.html',
which in essence does something similar to a 'hack' I was mentioning before with JSON.parse(JSON.stringify(scope.model.table.value))