Unable to add rows dynamically using records

That's normal since you are saving multiple files in the same variable (ri!upload).

Here is an example that might help understand

a!localVariables(
  local!pdfs,
  a!gridLayout(
    headerCells: { a!gridLayoutHeaderCell(label: "File") },
    rows: a!forEach(
      items: local!pdfs,
      expression: a!gridRowLayout(
        contents: {
          a!fileUploadField(
            value: local!pdfs[fv!index].fileId,
            saveInto: local!pdfs[fv!index].fileId,
            maxSelections: 1
          )
        }
      )
    ),
    addRowLink: a!dynamicLink(
      label: "Add new row",
      saveInto: {
        a!save(
          local!pdfs,
          append(local!pdfs, a!map(fileId: null))
        )
      }
    )
  )
)

You are trying to append the ri!  variable to a local variable . Can you specify what is the data passed to ri! is it the record structure .

Instead you can use the record type in the local variable and append it to the local variable local!pdf.