@wix-expert-velo-cert After the for loop runs, r.items is simply an array result of the above query with the kdtransfirm field updated for each of the items.
To state it another way, it’s not possible to do a wixData.update with an object that includes only an ID and the value of one field (kdtransfirm) and not have it remove the data in the other fields of the record. That is the way the function operates: It expects that when you update the record, you specify the values for all the fields that have data. That’s why the strategy of altering the one field in the result array that the original query produces, and then writing that back with a bulkUpdate, is a sensible choice. It will maintain the data of those other fields doing it that way.
I suggest that you put a console.log(r.items) after the for loop, and then examine the array. It’s important to understand what you’re dealing with.