Link Field in Child Table showing ID after setting, but showing name when clicking into field


I have a child table. In that child table I set a link field in every row on loading of the form.
The link field is read only.

for (const row of frm.get_field("child_table").grid.grid_rows) {
  row.doc["field"] = id

Now I see the ID of the linked object that I set by assigning the ID to the field.
However, I would like to see the name of the linked object.

And, after clicking on the read only link field, the correct name is shown until I click out of the field again.

Any idea what to do to permanently show the name?